The 6th International Conference on Bacterial Blight …icbb6.org/wp-content/uploads/2019/08/Abstract_Book.pdfThe 6th International Conference on Bacterial Blight of Rice 1 Sponsors

1

The 6th International Conference

on Bacterial Blight of Rice

Program and Abstract Book

Can Tho city, Vietnam

19-21 August 2019

The 6th International Conference on Bacterial Blight of Rice


“Together Towards a Sustainable Management of Bacterial Blight and Bacterial Leaf Streak of Rice”

Program and Abstract Book

Can Tho city, Vietnam

19-21 August 2019


Table of Contents

Sponsors............................................................................................................................................................. 1

Opening Remarks from Vice Minister, MARD ..................................................................................... 2

A Message from the Conference Organizers ........................................................................................ 4

About the Organizers .................................................................................................................................... 5

Executive Committee .................................................................................................................................... 6

Keynote Speakers’ Biography .................................................................................................................... 7

Conference Program ..................................................................................................................................... 9

Keynote Speech Abstracts: ...................................................................................................................... 13

Oral Presentations’ Abstracts ................................................................................................................. 17

Session I: Current Assessment of Bacterial Blight Disease ..................................................... 17

Session II: Epidemiology and Population Biology of Bacterial Blight ................................ 20

Session III: Host Resistance: Genetics and Molecular Biology .............................................. 23

Session IV: Disease Management and Breeding .......................................................................... 30

Session V: Molecular Interaction Between Host and X. oryzae pv. oryzae ........................ 40

Session VI: Integrative Genomics, Proteomics – Effectors, Epigenetics of Xoo ............... 46

Session VII: Biotech and Genome/Gene Editing ......................................................................... 49

Poster Presentations’ Abstracts ............................................................................................................. 51

ICBB06 List of Participants ...................................................................................................................... 68

General Information ................................................................................................................................... 76

Venue Maps .................................................................................................................................................... 80


1

Sponsors

Vietnam Ministry of

Agriculture and Rural

Development

Cuu Long Delta Rice

Research Institute

Bayer Vietnam Ltd.

Binh Dien

Fertilizer Joint

Stock Company

Dong Nam Seed Joint Stock

Company

Institut de recherche pour

le développement


2

Opening Remarks from Vice Minister, MARD

Distinguished Guests, Speakers, Sponsors, and Friends!

Welcome you All to Can Tho City of Viet Nam and to the 6th International

Conference on Bacterial Blight of Rice!

I am so pleased to see so many colleagues, professors, and friends from many

countries. This conference provides the opportunity for all of us to discuss and share

achievements and progress in studying bacterial blight and related subjects in rice.

As you know, global rice production has increased faster over the last decade and

most of the increase in rice production was due to higher yields. According to the

Food and Agricultural Organization (FAO) report, world rice production is estimated

to amount to 516.8 million tons (milled basis) in 2019, unchanged from the 2018 all-

time high. Under current prospects of rice production, global rice production will

remain the same in 2020. Vietnam is the world’s fifth-largest rice-producing country

and in the top 3 rice exporting countries in the world. FAO forecasts the 2019

Vietnam’s rice production at 28.3 million tons (milled basis), slightly decreased from

the previous year’s record level. However, there are some factors such as global

warming, environmental crisis, plant diseases and pests, including biofuel needs that

affect rice production in many countries, including Vietnam.

Bacterial blight is one of the most serious diseases of rice. The major effect of

bacterial blight disease on rice production is yield loss. The estimated yield losses due

to bacterial blight in tropical Asia vary from 2 to 74%, depending on location, season,

weather, crop growth stage, and cultivar. Globally, the effect of bacterial blight

disease in rice has been reported from different parts of the world from Asia to

northern Australia, Africa, and the United States. According to the report of Vietnam

Ministry of Agriculture and Rural Development (MARD), bacterial blight disease

negatively affected two major rice production areas, the Mekong and Red River

Deltas. In 2016, of 150.000 ha total bacterial blight affected areas, 19.045 ha were

severely yield loss countrywide. Whereas, 51.000 ha were damaged by this disease in

the southern provinces including the Mekong Delta, the largest rice production area in

Vietnam, contributing 54% of the country’s rice output and up to 90% of rice exports.

Thus, achievements and progress in studying of bacterial blight will be useful for

disease management and increasing rice production further.


3

It is a great honor and pleasure for us to hold the 6th International Conference on

Bacterial Blight in Can Tho city, the center of Mekong Delta. We hope this

conference will open new opportunities for cooperation in studying bacterial blight

and other related projects.

Through this conference, we would like to thank sponsors and organizations for your

support and help.

Enjoy your participation in the 6th International Conference on Bacterial Blight and

memorable time visiting Can Tho city.

Thank you for your attention and I wish you a very successful conference.

Le Quoc Doanh

Vice Minister

Vietnam Ministry of Agriculture and Rural Development


4

A Message from the Conference Organizers

Distinguish Guests, Ladies and Gentlemen!

Welcome to Viet Nam and Can Tho city for the 6th International Conference on

Bacterial Blight of Rice.

Like the previous conference in the Philippines, we are confident that the 6th

International Conference on Bacterial Blight of Rice in 2019 will provide a forum for

fruitful interaction and exchange of ideas between the participants coming from

around the world.

Bacterial blight is the most important bacterial disease in rice which can cause up to

74% of yield loss due to its high epidemic potential. This year, we are glad to note that

15 different countries from around the world are represented by the authors and

participants, thereby making it a truly international event. The technical program

covers three days of presentations including three keynote speeches, 33 oral

presentations and 17 posters, and a field trip to CLRRI. So, we expect you to have a

great time during these three days.

No conference can be successful without excellent teamwork and ours is no different.

Our special appreciations also go to the sacrifices and perspirations of our colleagues

at CLRRI and the all local committee members in making this conference a smooth

process.

I would like to thank the members of the international organizing committee, the

speakers, and the presenters, who have made so many efforts for the preparation of

their latest researches and the keynote speakers who kindly accepted sharing their

expertise with the attendees.

I would like to sincerely thank the many sponsors who made the 6th International

Conference on Bacterial Blight of Rice possible. Without their support, the conference

would not be financially viable for members.

Most of all, thank you for attending ICBB06 2019. We hope this conference will

benefit all of us in advancing research activities and building new friendship.

I hope you enjoy the conference and Can Tho city.

Tran Ngoc Thach

Chair, Local Organizing Committee

http://www.siam.org/meetings/dm98/committe.htm

http://www.siam.org/meetings/dm98/program.htm


5

About the Organizers

The Cuu Long Delta Rice Research Institute (CLRRI) is the premier national institute

specialized in rice research and education, headquartered in Can Tho city, the center

of the Mekong delta of Vietnam. The institute, founded in 1977 by the Vietnamese

government, is the major force in Vietnam agricultural science and plays a leading

position in the nation as a dynamic source for innovative research and teaching.

CLRRI works closely with industry, business and public research bodies nationally

and internationally to ensure its programs are relevant to today’s fast-paced and ever-

changing world. The primary functions of the institute are as follow: i) To carry out

basic and applied research in all disciplines of rice, rice-based crops, and agricultural

systems in the Mekong Delta region towards sustainable agriculture; ii) To set up and

implement research programs in collaboration with national and international

organizations in rice research and rice-based farming systems; iii) To transfer

scientific and technical advances in agriculture to public and private sectors; and iv)

To train nationwide agro-technical staffs and farmers to produce and supply rice seed

stock. Over 42 years of the establishment, more than 180 new varieties have been

developed by CLRRI and released to farmers under the name OM rice variety. More

than 70% of about 4,2 million hectares of total rice-growing area annually in the

Mekong delta has been covered by the OM rice varieties in the last decade. The

institute has also developed and introduced new and improved methods and

technologies to farmers for sustainable and profitable management of their crops.

Besides, OM rice varieties have also been grown in different countries in Asia, Africa,

and Latin America.


6

Executive Committee

International Committee

▪ Dr. Le Quoc Doanh, Vice Minister, Ministry of Agriculture and Rural

Development (MARD), Vietnam

▪ Dr. Nguyen Hong Son, President, Vietnam Academy of Agricultural

Sciences, Vietnam

▪ Dr. Wolf B. Frommer, Institute for Molecular Physiology,

HHU, Düsseldorf, Germany

▪ Dr. Jan E. Leach, Colorado State University, USA

▪ Dr. Ralf Koebnik, Director of Research, Institute of Research for

Development, France

▪ Dr. Adam J. Bogdanove, Cornell University, USA

▪ Dr. Jagjeet Singh Lore, Punjab Agricultural University, India

▪ Dr. Chenyang He, Chinese Academy of Agricultural Sciences, China

▪ Dr. Ricardo Olivera, International Rice Research Institute

▪ Dr. Gongyou Chen, Shanghai Jiaotong University, China

▪ Dr. Lin-Woo Kang, Konkuk University, South Korea

Local Organizing Committee

▪ Dr. Tran Ngoc Thach, CLRRI (Chair)

▪ Dr. Huynh Van Nghiep, CLRRI

▪ Dr. Nguyen Thuy Kieu Tien, CLRRI

▪ Dr. Hoang Dinh Dinh, CLRRI

▪ Dr. Duong Hoang Son, CLRRI

▪ Dr. Nguyen Thi Phong Lan, CLRRI

▪ Dr. Nguyen The Cuong, CLRRI

▪ Ms. Nguyen Thi Khao, CLRRI


7

Keynote Speakers’ Biography

Dr. Casiana Vera Cruz

Dr. Casiana M. Vera Cruz or "Nollie" is recognized for her

important contributions in the field of plant pathology (Senior

Scientist II) at the Host Plant Resistance Cluster, Rice Breeding

Platform at the International Rice Research Institute. With

expertise in plant pathology, she was responsible for researches on

pathogen biology, especially her early work on bacterial blight of

rice, population biology, host-pathogen interaction, and host plant

resistance to diseases. She developed and refined molecular

markers for both Xoo and rice R genes and has contributed to

resistance improvement to BB and other diseases in different rice

ecosystems in collaboration with breeders. She also led the IRRI-

DA Heirloom Rice Project which aims to raise productivity and

enrich the legacy of traditional rice through empowering

communities in unfavorable rice-based ecosystem. Currently, she

is engaged in coordination of IRRI research portfolio for the

Philippines.

Professor Jan Leach

Prof. Jan Leach is a plant pathologist who studies the

molecular basis of plant disease susceptibility and resistance

and how these responses are influenced by interactions

within the phytobiome. Prof Leach is the current President of

the International Society of Plant Pathology. She is a Fellow

and a past President of the American Phytopathological

Society (APS). She served on the APS Public Policy Board

for 16 years, leading advocacy efforts such as the

Phytobiomes Initiative, a systems-level approach to

improving crop productivity. Prof Leach is a Fellow of the

American Association for the Advancement of Science

(AAAS) and a Fellow of the American Academy of

Microbiology. She is a member of the Board on Agriculture

and Natural Resources of the US National Academy of

Sciences, and a Non-Resident Fellow of the Noble Research

Foundation Institute. Recently, Prof. Leach has received

the Agropolis Louis Malassis International Scientific Prize

for Agriculture and Food in Montpelier, France, during

the 4th World Congress on Agroforestry in May.


8

Professor Wolf B. Frommer

Dr. Wolf B. Frommer is Professor and Head of the Institute

for Molecular Biology, Heinrich Heine

University Düsseldorf 2017 - present). He earned his Ph.D.

in Biology with Peter Starlinger at the University of Cologne

in 1987 and was an Independent group leader at the Institute

for Genebiological Research in Berlin. His lab pioneered the

development of metabolite sensors (e.g. sugars, amino

acids), hormones (ABA, gibberellin) and reporters of

transporter activity (ammonium, nitrate and peptide

transporters). A recent development is the Matryoshka

concept that enables ratiometric measurements with single-

fluorophore sensors. His lab was also the first to identify and

characterize the role many of the the key transporters from

plants (sucrose, amini acids, ammonium, peptides,

nucleobases) and is developing plants that are resistant to

pathogens. Recent recognitions include the Laurence

Bogorad Award for Excellence in Plant Biology, 2012,

election to the German National Academy of Sciences

Leopoldina, 2015, the Alexander von Humboldt

Professorship – International Prize for Research in Germany,

2016 and the Tsungming Tu award 2018.


9

Conference Program

Monday - August 19, 2019 (Day 1)

07:30 Registration Local Organizer

08:30 Opening Remarks Dr. Le Quoc Doanh

Vice Minister, MARD, Vietnam

08:40 Message from the Organizer Dr. Tran Ngoc Thach

Director, CLRRI, Vietnam

08:50 Congratulation Address TBD

Leader of Can Tho City

08:55 Message from the Sponsor Mr. Bui Van Kip

Bayer Vietnam Ltd.

09:00 Introduction to Keynote Speaker Dr. Jan Leach

Colorado State University, USA

09:05

Keynote Speech: Bacterial Blight of Rice: A

Four Decade of Research and Partnership

for Sustainable Rice Production

Dr. Casiana M. Vera Cruz

IRRI, Philippines

09:35 Special Event: Recognition of Dr Casiana

M. Vera Cruz Contribution to the Bacterial

Blight of Rice Research Community

Dr. Jan Leach

Colorado State University

USA

09:45 Group Photo Session

10:00 Coffee Break

10:15 Introduction to Keynote Speaker Dr. Ricardo Oliva

IRRI, Philippines

10:20 Keynote Speech: Managing Rice Bacterial

Blight in a Changing Climate

Dr. Jan Leach

Colorado State University, USA

Chair: Dr. Nguyen Hong Son, VAAS, Vietnam

10:50 Genotypic and pathotypic diversity of

bacterial blight diseases (Xanthomonas

oryzae pv. oryzae) in the Mekong Delta of

Vietnam

Dr. Nguyen Duc Cuong

Cuu Long Delta Rice Research

Institute, Vietnam

11:15 Monitoring of bacterial blight populations

in the field

Dr. Ricardo Oliva

IRRI, Philippines

11:40 Diversity of bacterial leaf blight diseases

strains (Xanthomonas oryzae pv. oryzae) in

Northern Vietnam

Dr. Tong Van Hai

Vietnam National University of

Agriculture, Vietnam

12:05 The evolutionary ebb and flow of tissue-

specificity and Xanthomonas vascular

pathogenesis

Dr. Jonathan M. Jacobs

Ohio State University, USA

12:05 Luncheon 12:05-13:30


10

Chair: Dr Wolf Frommer, Heinrich Heine University, Germany

13:30 Pathogenic and Molecular Diversity of

Xanthomonas oryzae pv. oryzae Population

Affecting Rice Granaries in Malaysia

Mrs. Kogeethavani R

Malaysian Agriculture and

Development Institute, Malaysia

13:55 Evaluation of the resistance of rice

lines/varieties to bacterial leaf blight

(Xanthomonas oryzae pv. oryzae) in the

North of Vietnam

Dr. Nguyen Huy Chung

Plant Protection Research Institute,

Vietnam

14:20 Characterization of the bacterial blight and

bacterial leaf streak resistance locus Xo1 in

Carolina Gold Select rice by Nanopore-

based whole genome sequencing

Dr. Adam J. Bogdanove

Cornell University, USA

14:45 Introgression of Leaf Blight Resistance

Genes into Indica Cultivar BT7 through

Marker-Assisted Backcrossing

Dr. Pham Thien Thanh

Field Crops Research Institute,

Vietnam

15:10 Coffee Break

Chair: Dr. Lin-Woo Kang, Konkuk University, Korea

15:25 Detection and grouping rice cultivars based

on the presence of Xa-genes in Situbondo

and Jember, Indonesia

Dr. Hardian Susilo Addy

University of Jember,

Indonesia

15:50 Overexpression of Antisense MIR396e

Confers Bacterial Blight Resistance through

Interfering Accumulation of miR396e/f-3p

in Rice

Dr. Huamin Chen

Chinese Academy of Agricultural

Sciences, China

16:15 Advances in Bacterial Blight of Rice: R

Genes versus Pathogen Population Structure

in South and South-East Asia

Dr. Jagjeet Singh Lore

Punjab Agricultural University,

India

16:40 Identification of QTLs Associated with

Bacterial Leaf Blight Resistance in

Khangdan18 Cultivar

Dr. Nguyen Quoc Trung



16:45 Poster Presentations 16:45-15:45

18:00 Welcome Reception 18:00-20:30


11

Tuesday - August 20, 2019 (Day 2)

Chair: Dr. Adam Bogdanove, Cornell University, USA

08:00 Introduction to Keynote Speaker Dr. Adam Bogdanove

Cornell University, USA

08:05 Keynote Speech: Engineering pathogen

resistance faster than pathogens can evolve

new virulence mechanisms?

Dr Wolf Frommer

Heinrich Heine University,

Germany

08:35

Development of bacterial leaf blight resistant

hybrids for sustainable rice farming

Dr. Deo Mishra

Bayer BioScience, India

09:00 Marker-assisted Breeding for Resistance to

Bacterial Leaf Blight in DT82 Rice Variety

Dr. Vo Thi Minh Tuyen

Agricultural Genetics

Research Institute, Vietnam

09:25

Profiling endophytic microbiome in bacterial

blight diseased leaves of rice identifies

bacterial endophytes with pathogen

antagonism and disease suppression

Dr. Fenghuan Yang


Sciences, China

09:50 Phage therapy in controlling rice bacterial leaf

blight caused by Xanthomonas oryzae pv.

oryzae

Dr. Nguyen Thi Thu Nga

Can Tho University,

Vietnam

10:15 Coffee Break 10:15-10:25

Chair: Dr. Ricardo Oliva, IRRI

10:25 Characterization of Bacteriophages Infecting

Xanthomonas oryzae pv. oryzae

Ms. Rejeki Desi

University of Jember, Indonesia

10:50 Biological control of Bacterial Leaf Blight of

Rice by Bacillus strains in the Mekong Delta:

Current status and future prospects

Dr. Tran Vu Phen

Can Tho University, Vietnam

11:15 Eco-friendly Management of Bacterial Leaf

Blight Disease of Rice in Kuttanadu, India

Dr. Reeny Zacharia

Rice Research Station, Kerala

India

11:40 Defense Biochemical Alterations in Rice

Leaves on Induced Resistance against


Dr. Le Thanh Toan

Can Tho University,

Vietnam

12:05 Xanthomonas oryzae-Triggered Production of

Atypical Rice Small RNAs During

Infection

Dr. Sebastian Cunnac

IRD, France

12:30 Luncheon 12:10-13:30

Chair: Dr Jagjeet Singh Lore, Punjab Agricultural University, India

13:30 The RpoN2-PilRX system regulates type VI

pilus-dependent motility and is required for

virulence in Xanthomonas oryzae pv. oryzae

Dr. Chao Yu


Sciences, China


12

13:55 Combined Transcriptome and Proteome

Analysis of the Pathogenicity-activated


Dr. Lin-Woo Kang

Konkuk University,

Korea

14:20 Xanthomonas oryzae pv. oryzae T3SS-

effector XopF interacts with multiple rice

targets to subvert the immune responses

during bacterial blight development

Dr. Kalyan K. Mondal

Indian Agricultural Research

Institute, India

14:45 Xylose-dependent hrp gene expression in


Dr. Seiji Tsuge

Kyoto Prefectural University,

Japan

15:10 Bioinformatic approaches to uncover genetic

acquisitions associated with epidemic

populations of Xanthomonas oryzae pv. oryzae

Dr. Alvaro L Perez-Quintero

Colorado State University,

USA

15:35 Coffee Break

Chair: Dr. Jan Leach, Colorado State University, USA

15:50 Quorum sensing and Xanthomonadin

biosynthesis in the phytopathogen

Xanthomonas

Dr. He Ya-Wen

Shanghai Jiao Tong University,

China

16:15

Getting into the weeds: How monitoring

Xanthomonas species outside the paddy can

inform crop management and our

understanding of pathogen evolution

Dr. Jillian Lang

Colorado State University,

USA

16:40 OsERF#123, a new susceptibility gene for

bacterial blight of rice

Dr. Mathilde Hutin

IRD, France

17:05 Legal Framework for Genome Editing

Approaches in Agricultural Development

Dr. Sarah Schmidt

Heinrich Heine University,

Germany

17:30 Wrap-up, Closing Remarks and

Announcement of the 7th ICBB

Dr. Wolf Frommer /

Dr. Tran Ngoc Thach

Wednesday - August 21, 2019 (Day 3)

CLRRI Field Tour

08:00 Bus from Can Tho to CLRRI Headquarter

09:00 Visit CLRRI Research/Experimental Fields

09:45 Visit Variety Demonstration Fields

10:30 Introduction to CLRRI CLRRI Conference Room


13

Keynote Speech Abstracts:

Bacterial Blight of Rice: A Four Decade of Research and Partnership for

Sustainable Rice Production

Vera Cruz CM

International Rice Research Institute, Los Banos, Laguna 4031 Philippines

Effective management of rice diseases is critical to sustaining rice productivity.

Despite knowledge of the disease over a century ago, bacterial blight (BB) of rice

caused by Xanthomonas oryzae pv. oryzae (Xoo) remains a serious threat to rice

production, especially with a warming climate and increasing frequency of extreme

weather events that predispose the disease. The importance of BB was fully

recognized when high yielding varieties lacking resistance were deployed widely in

the late 1960s. As host plant resistance is the most economical and ecological

approach to manage the disease, IRRI scientists have initiated research on variability

of Xoo, beginning in the late 1960s, and studied its population structure across

countries and regions. This work was accomplished through organized partnerships

with national programs in Asia and advanced research institutions in the US and

Europe in the mid-1980s to early 2000s (ARBN), and globally through CGIAR

Programs (GCP) in mid-2000s. Rice genetic resources, such as rice differentials,

resistance sources, near-isogenic lines (NILs), and pyramids in elite backgrounds were

developed in collaborations between Japanese and IRRI breeders using well-

characterized physiological Xoo races and strains. Advances in molecular genetics

and genomics-enabled approaches provided powerful insights into Xoo biology and

evolution as well as disease epidemiology and deployment strategies for resistance

sources. These studies revealed the contributions of avirulence/virulence genes to Xoo,

fitness in the field, and their utility in prediction of Xa-gene durability. In the late

1990’s, molecular markers for mapped R-genes were developed; these were refined

with advances in sequencing, genomics and analytical approaches, and cloning of R-

genes. The various platforms developed from these have been refined, shared, and

applied in international and national breeding programs, including private

organizations. These organized partnerships continue in breeding networks in Asia

and Africa. Productive collaborations with breeders have resulted in the release of

better combinations of Xa genes in popular varieties and elite backgrounds, and

effective combinations of Xa genes with other disease R genes and abiotic stress

tolerance genes/QTL. With precise diagnostic SNP markers for both rice and Xoo,

resistances are strategically deployed more efficiently and effectively in real-time at a

global scale.

On the pathogen side in the mid-2000s, the availability of published Xanthomonas

genome sequences led to exciting discoveries of transcription activator-like (TAL)

effectors in Xoo, and the corresponding susceptibility targets, SWEET sucrose

transporters, in rice. Modification of the SWEET genes through genome editing

technologies is being used to enhance resistance in a highly precise and targeted way

and will be reported in this conference by partners in the US and Europe.


14

Finally, enriching our partnerships will continue to address the challenges in

sustaining a healthy rice production environment. Pursuing our goal, the 6th ICBB

provides an excellent opportunity to share progress and identify research areas for Xoo

and BB as a focus for the next 10-20 years.

Keywords: Xanthomonas oryzae pv. oryzae races, fitness, near-isogenic lines, gene

pyramids


15

Managing Rice Bacterial Blight in a Changing Climate

Jan E. Leach, Stephen Cohen and Jennifer Shipp

Colorado State University, Fort Collins, CO, USA

Phenotypic responses of plants to biotic and abiotic stresses are frequently studied as

the outcome of interactions between plants and one or two species of microbes or a

single abiotic stress. However, in the phytobiome, plant health and productivity are

impacted by simultaneous interactions among multiple organisms and the

environment, and frequently, the responses to these interactions are distinct and would

not be predicted from studying less complex systems. Many plant diseases are

predicted to intensify as environmental temperatures increase, and, to compound the

problem, many widely used sources of disease resistance fail to control disease at high

temperatures. The molecular mechanisms for how plants respond to simultaneous

heat- and pathogen-imposed stresses, however, are not known. From a meta-analysis

of publicly available rice stress response transcriptome data, we demonstrated that rice

generally up-regulates hormone-responsive genes during stress responses, most

notably genes in the abscisic acid (ABA) pathway. This is consistent with our findings

on the impacts of high temperature on bacterial blight (BB) disease and resistance.

Heat stress increases susceptibility of rice to Xanthomonas oryzae pv. oryzae (Xoo),

and most BB resistance genes are not effective at high temperatures. Of seven BB

resistance genes tested so far, only one, Xa7, is more effective at elevated

temperatures. A transcriptomics experiment involving rice plants infected with Xoo

during high temperature stress revealed an upregulation of ABA pathway genes,

consistent with higher levels of disease. In plants expressing Xa7-based resistance at

high temperature, however, the ABA pathway genes were downregulated. This trend

suggests that during simultaneous heat and disease stresses, plants undergoing an Xa7-

based resistance prioritize response to pathogen over the response to abiotic stress.

Ongoing research is focused on understanding how these pathways contribute to

increased plant disease at high temperature, the impact of other abiotic stresses on

disease and resistance, and how we can translate this information to develop more

effective control of bacterial diseases in the face of a changing climate.

Keywords: biotic stress, abiotic stress, climate, ABA, phytobiome


16

Engineering Pathogen Resistance Faster Than Pathogens Can Evolve New

Virulence Mechanisms?

Joon Seob Eom1, Ricardo Oliva3, Frank F White4, Bing Yang5 and Wolf B Frommer12

1Institute for Molecular Physiology, Heinrich Heine Universität Düsseldorf and Max

Planck Institute for Plant Breeding Research, Köln, Germany 2Department of Plant Biology, Carnegie Science, Stanford, CA 94305, USA 3International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines 4Department of Plant Pathology, University of Florida, 32611, USA 5Division of Plant Sciences, University of Missouri – Columbia, MO65211, USA

At present, we only partially understand how assimilates are translocated from leaves

into seeds. We identified a new class of transporters for cellular uptake and efflux of

sugars (SUTs and the SWEETs). They were identified in Arabidopsis and we

analyzed their roles in the physiology of both Arabidopsis and crop plants. We found

that three SWEET13 paralogs play critical roles in phloem loading in maize and

identified SWEET4c as a hexose transporter in the basal endosperm transfer cell layer

of maize kernels. We identified SWEET11 and 15 as key transporters during seed

filling in rice. We try to establish the complete path of sugars from the site of

synthesis to the ultimate storage site. We develop fluorescent biosensors for sugars

and transporter activity and are exploring the regulation of the transport processes.

Surprisingly, we found that SWEETs function as pathogen susceptibility factors.

Xanthomonas oryzae pv oryzae (Xoo), the causative agent of leaf blight in rice, uses

TAL effectors to ectopically induce the expression of specific sets of SWEET genes.

If SWEET gene induction is blocked, e.g. by genome editing of effector binding sites,

the resulting plants are resistant. We engineered a large number of R gene variants

that can be deployed in intelligent manner possibly at a pace relative to the spread of a

pathogen that created a new TAL effector for inducing alternative SWEETs. We have

implemented these R gene variants in elite rice varieties and intend to provide them to

breeders for dissemination, in particular to subsistence farmers. To be able to deploy

the best possible R gene combination, we also developed a diagnostic kit that allows

rapid testing of new Xoo isolates. The simplest hypothesis is that SWEETs serve in

pathogen nutrition, we can however not exclude that the consequence of SWEET

induction is priming of defense pathways. We have begun now exploring the SWEET-

related disease mechanism.

Keywords: effector, sugar transporter, R gene, SWEET


17

Oral Presentations’ Abstracts

Session I: Current Assessment of Bacterial Blight Disease

Genotyic and Pathotypic Diversity of Xanthomonas oryzae pv. oryzae

Causing Rice Bacterial Leaf Blight in the Mekong Delta of Vietnam

Nguyen Thi Phong Lan, Tran Thi Nam Ly, Tran Ha Anh, Nguyen Thi Xuan Mai, Tran

Phuoc Loc, Vo Thi Thu Ngan, Tran Thi Kieu, Vo Thi Da Thao, Nguyen Duc Cuong

Plant Protection Department, Cuu Long Delta Rice Research Institute, Vietnam

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a

major rice disease which reduces grain quality and yield of rice. Bactericides, culture

practices and resistant varieties have been developed for BLB management. Among

control measures, planting resistance varieties has been considered as the most

effective, sustainable and ecofriendly approach. Development of good resistance

varieties depends on knowledge of BLB resistance gene and pathotypes diversity of

Xoo population. The virulent study was conducted on 12 near-isogenic lines (IRBB1,

IBB2, IRBB3, IRBB4, IRBB5, IRBB7, IRBB8, IRBB10, IRBB11, IRBB13, IRBB14,

IRBB21), each harboring a single resistance gene together with IR24 and Xoo strains

collected from 8 provinces in the Mekong delta of Vietnam from 2017 - 2018. All

strains of Xoo were virulent to the resistance genes (Xa1, Xa2, Xa10, Xa11, Xa13), in

contract Xa5 was effective against almost strains of Xoo population. Total 13

pathotypes were identified regarding reaction between Xoo strains and the differential

lines. Among these, P10 was highly virulent which showed susceptible to all single

BLB resistance genes. In addition, P9 was found as the most popular pathotype and

was distributed throughout 6 provinces in the region. For genetic characterization, 34

strains of Xoo were analyzed by polymerase chain reaction (PCR) using two PCR-

based assays. A high level of genetic polymorphism was found and the strains were

grouped into 2 clusters. Evaluation of 30 widely grown and promising rice varieties

(original from Vietnam and IRRI) for its reaction against Xoo strains belonging to

different pathotypes was conducted under greenhouse conditions. All of Vietnamese

and IRRI improved varieties were susceptible to the pathotypes that were inoculated.

This study indicated that, there was no correlation between pathotypes and genetic

clusters because each genetic cluster involves Xoo strains regarding different

pathotypes. Single resistance gene could not give broad-spectrum resistance against

Xoo population in the Mekong delta, except Xa5 is widely effective.

Keywords: bacterial leaf blight of rice, near isogenic line(s), resistance gene,

pathotype


18

Monitoring of Bacterial Blight Populations in the Field

Ricardo Oliva

Rice Breeding Platform, International Rice Research Institute

The emergence of highly aggressive clones of plant pathogens in agricultural

ecosystems represents an important threat to food security. Bacterial blight, caused by

Xanthomonas oryzae pv. oryzae (Xoo), is the most important bacterial disease of rice

in Asia. The pathogen appears to evolve a number of populations showing distinctive

patterns of interaction with rice resistance gene (Xa). In that scenario, knowledge on

the distribution of populations may be critical to predict seasonal disease outcomes

and reduce the risk of yield loss. Using genomic and phenotypic information on a

large set of Xoo strains, we developed stable molecular markers that can distinguish

pathogen populations. Moreover, the markers appear to be highly sensitive in a wide

range of samples, from DNA to infected-leaf samples. Using field experiments, we

demonstrated that real-time surveillance of Xoo populations is possible during the

cropping season. More importantly, the markers have been transferred to a

commercial platform, allowing other users to benefit from this technology. We expect

in the near future that high-throughput and rapid monitoring of rice-growing areas in

Asia will drive deployment and genetic improvement effort in the region.

Keywords: disease outbreaks, host plant resistance, surveillance, race-specificity


19

Diversity of Xanthomonas oryzae pv. oryzae Strains Causing Bacterial

Blight of Rice in Northern Vietnam

Hai Tong Van, Trung Nguyen Quoc, Chau Nguyen Thi Cam, Hien Phan Thi and

Hanh Nguyen Thi Thuy

Faculty of Biotechnology, Vietnam National University of Agriculture, Ha Noi,

Vietnam

Bacterial leaf blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of

the most severe diseases in rice – cultivating areas of Vietnam. Recently, it not only

caused damage season crop but also in spring season and resulted in great loss of yield

and quality. To prevent this disease, the use of resistance varieties offers the most

economical efficiency. In order to breed resistant varieties, it is necessary to study on

diversity of Xoo strains, as well as the distribution of each strain and identify to

resistance genes for each strain.

In this study, we conducted the collection, isolation and identification of bacterial leaf

blight diseases strains through reaction with near isogenic lines and comparing the

diversity of current strains with 2012 strains. Seventy-two disease samples were

collected on 29 rice varieties in 15 provinces in North Vietnam. In these samples, 146

isolates were screened and isolated by XORF & XOR marker. Seven strains were

identified by inoculation in near isogenic lines are 2A, 3A, 4, 5A, 7, 11 and 12 strain.

2A, 3A and 5A strain were most common. Strain 12 had highest pathogenicity. Xa5

and Xa7 gene were the most resistant genes. The distribution of Xoo strains was

mapped. Comparing the current strains with the strains of 2002 found that the strains

composition was less, but strains 5A was more widely distributed.

Keywords: bacterial leaf blight, isogenic, isolate, Xanthomonas oryzae pv. oryzae,

inoculation, resistance genes.


20

Session II: Epidemiology and Population Biology of Bacterial Blight

The Evolutionary Ebb and Flow of Tissue-Specificity and Xanthomonas

Vascular Pathogenesis

Jonathan M. Jacobs

Department of Plant Pathology and Infectious Disease Institute, Ohio State University,

Columbus, OH, USA

Plant pathogenic Xanthomonas bacteria cause vascular and non-vascular diseases of

over 200 plant species. The factors that contribute to Xanthomonas evolution for

niche-specific, vascular or non-vascular behavior remain unclear. We examined the

molecular and evolutionary basis for vascular pathogenicity in Xanthomonas species.

We found a single gene cbsA, which distinguishes vascular from non-vascular Gram-

negative plant pathogens. Among all sequenced plant-associated microbes, cbsA,

which encodes a cellobiosidase, was conserved in vascular pathogens from three

distinct genera: Xanthomonas, Xylella, and Ralstonia. Heterologous expression of

cbsA in non-vascular Xanthomonas species resulted in pathotype conversion allowing

for xylem colonization, while its deletion in vascular species resulted in the loss of

xylem colonization, demonstrating that cellobiosidase activity is both sufficient and

necessary for vascular colonization. Notably heterologous expression of CbsA

permitted pathotype conversion, enabling apoplast barley and rice Xanthomonas

pathogens to cause xylem, blight pathogenesis. We inferred several instances of

concomitant gain and loss of cbsA and vascular pathogenicity in Xanthomonas, where

cbsA was acquired through horizontal gene transfer in what are now vascular lineages,

and alternatively lost through transposon mediated insertion in non-vascular lineages.

The dynamic evolution of cbsA suggests that rather than representing evolutionary

endpoints, vascular and non-vascular modes of infection exist on a continuum, and

populations easily flow from one end to another depending on the selective

environment.

Keywords: evolution, vascular, xylem, pathogen, Xanthomonas


21

Molecular Identification and Characterization of Xanthomonas oryzae pv.

oryzae Isolated from Different Rice Growing Areas of Pakistan

Sumera Yasmin1, Ali Faiq1, Khansa Ejaz1, M. Asif1, M. Asif1, M. Hanna Nguyen2,

C.M. Vera Cruz2, Ricardo Oliva2 and M. Arif1

1National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad,

Pakistan 2 International Rice Research Institute (IRRI) Los Banos, Philippines

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo), is one of

the major threats to rice as it reduces yield and grain quality in all rice growing areas.

The study has been conducted for molecular characterization and screening of

Pakistani strains of Xoo against different varieties of rice. Molecular detection of the

pathogen was carried out using species and pathovar specific primers. LAMP was

used to study genetic relatedness of newly isolated Xoo strains. Different isolates of

the pathogen were confirmed in vivo by pathogenicity tests using clip inoculation

method under net house conditions. Screening of different Xoo isolates against

different varieties of rice was carried out to determine the most effective R gene or

combination of R genes against Xoo and to identify the most virulent strain. The

present study provided significant information to find the best combination of R genes

to develop BLB resistant rice varieties.

Keywords: pathogen, strain, R genes, Xanthomonas oryzae


22

Pathogenic and Molecular Diversity of Xanthomonas oryzae pv. oryzae

Population Affecting Rice Granaries in Malaysia

Kogeethavani R1, Suzianti I.V1, Fatin Nurliyana A1, Nurshamiza M.Y1

1Rice and Paddy Research Centre, Malaysian Agriculture and Development Institute,

Selangor 43400, Malaysia

The bacterial blight disease (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is

one of the major diseases of economically importance in Malaysian rice production. It

became increasingly evident in recent years due to its severe outbreaks in 2013 -2017

in most rice growing states in the country. No local varieties were found resistance to

this disease. Breeding for resistance is the most practical and cost-effective approach

for sustainable management. The purpose of this study is to obtain information on the

pathogenic and haplotypic variability of Xoo to develop an effective breeding strategy

for BB resistance. Among forty-two isolates assessed for their interactions with 10

near-isogenic rice lines (NILs) with known single resistance genes (Xa genes), 16

pathotypes (Pxo-1 to Pxo-16) were identified. Pathotype Pxo-1 showed incompatible

interaction with all the Xa genes and was the predominant with highest pathotype

frequency (21%). Pathotypes Pxo-14, Pxo-15, and Pxo-11 also considered as a major,

containing pathotype frequency between 11-14%. In rest of designated pathotypes,

Xoo isolates had incompatible interaction with one or more Xa genes except for Xa5

gene which had incompatible interaction to all the Xoo isolates. Conferring resistance

against 100% of the isolates, Xa5 emerged as the most effective gene, followed by

Xa7 (92 %), Xa14 (76 %) and Xa21 (69 %). Thirty haplotypes were detected among

the Xoo population at 58% similarity using rep-PCR fingerprinting. However, a weak

correlation was observed between the pathotypes and these haplotypes. This suggests

a high degree of DNA polymorphism among strains within many pathotypes. Lowest

disease severity and virulence frequency were observed on NILs carrying Xa5, Xa7,

Xa14 and Xa21 genes indicating their potential use as donor parent in a breeding

program. Incorporation of these four genes appears to be the most suitable Xa gene

combination to be deployed in Malaysian rice cultivars.

Keywords: pathotypes, haplotype, Xa gene effectiveness, Xanthomonas oryzae, near

isogenic lines


23

Session III: Host Resistance: Genetics and Molecular Biology

Evaluation of the Resistance of Rice Lines/Varieties to bacterial leaf blight

(Xanthomonas oryzae pv. oryzae) in the North of Viet Nam

Nguyen Huy Chung, Nguyen Tien Hung, Nguyen Thi Tho, Le Thi Phuong Lan,

Lam Thi Nhung

Plant Protection Research Institute, Hanoi, Vietnam

Bacterial leaf blight (Xanthomonas oryzae pv. oryzae), is a major disease of rice in the

tropics and subtropics of Asia countries (Mew.1987). Bacterial leaf blight can cause

severe yield loss of up to 50% - 70% in severely infected fields (Mew.1987). In Viet

Nam, Bacterial leaf blight (BLB) is one of the destructive diseases and occurs year-

round depending on the regions. In the North, the disease usually appears in the

summer crop season. However, it occurs more and more often and can cause serious

damage in the winter-spring crop season. The effectiveness of control BLB is limited.

Thus, utilizing resistant varieties is a good strategy for disease management. Study on

population diversity of pathogen, varieties tolerance/ resistance has been focused in

many countries (Maryam, et al.2012, Lu, et al.2014, Liu et.al.2017). This research will

focus on the evaluation the resistance of near isogenic lines (NIL) to BLB and

screening the resistance of rice varieties to BLB in the North of Viet Nam.

Twenty-eight NIL lines conferring one or more resistant genes were inoculated with

twenty-eight isolates of X. oryzae pv. oryzae collected from 15 provinces using

clipping inoculation method. One hundred and fifty traditional rice varieties and forty-

four popular cultivated varieties were also screened for BLB resistance. Scores were

recorded following the Standard Evaluation System for Rice (IRRRI, 2014).

The result shows that among NIL lines, IRBB4, IRBB5, IRBB21 were the lines with a

single gene (Xa4, xa5, Xa21 respectively) more resistant to BLB. These lines were

resistant/medium resistant to 54-87% isolate inoculated. In addition, NIL lines

conferring multiple genes revealed more resistant to BLB than the single gene NIL.

Ten lines were resistant to more than 50% isolate inoculated, in which IRBB53

(xa5/xa13), IRBB50 (Xa4/xa5), IRBB54 (xa5/Xa21) were resistant to 85%, 66% and

64% isolate of BLB pathogen in this study. In the traditional varieties group, there

were 18 resistant varieties (score 3), 64 medium resistant varieties (Score 5), and 24

susceptible varieties (Score 7-9) account for 12 %, 64% and 24% of the total

respectively. There was a high percentage (62%) of susceptible varieties within

popular varieties, whereas 18 % resistant, and 20% medium resistant varieties

recorded.

This study indicates that resistant genes Xa4, xa5, Xa21 and resistant traditional

varieties can be used for breeding for BLB resistance in the North of Viet Nam and

more research on pathotype of BLB need to be conducted.

Keywords: Bacterial leaf blight, Xanthomonas oryzae pv. oryzae, NIL, resistant gene.


24

Characterization of the Bacterial Blight and Bacterial Leaf Streak

Resistance Locus Xo1 in Carolina Gold Select Rice by Nanopore-based

Whole Genome Sequencing

Andrew C. Read1, Matthew J. Moscou2, Aleksey V. Zimin3, Geo Pertea3, Rachel S.

Meyer4†, Michael D. Purugganan4,5, Jan E. Leach6, Lindsay R. Triplett6††, Steven L.

Salzberg3,7, and Adam J. Bogdanove1*

1Plant Pathology and Plant Microbe Biology Section, School of Integrative Plant

Science, Cornell University, Ithaca, NY USA 2The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH UK 3Center for Computational Biology, McKusick-Nathans Institute of Genetic Medicine,

Johns Hopkins School of Medicine, Baltimore, MD, USA 4Center for Genomics and Systems Biology, New York University, New York, NY USA 5Center for Genomics and Biology, New York University Abu Dhabi, Saadiyat Island,

Abu Dhabi, United Arab Emirates 6 Department of Bioagricultural Sciences and Pest Management, Colorado State

University, Fort Collins, CO USA 7 Departments of Biomedical Engineering, Computer Science, and Biostatistics, Johns

Hopkins University, Baltimore, MD USA

We recently mapped the Xo1 locus for resistance to bacterial blight and bacterial leaf

streak, found in the American heirloom rice variety Carolina Gold Select, to a region

that in the Nipponbare reference genome is rich in NLR genes. NLR genes are often

clustered, evolving via duplication, contraction, and transposition. This complexity

makes NLR gene-rich regions of a genome challenging to assemble by short-read

sequencing. Sequence capture by hybridization approaches, such as RenSeq, have

been used to catalog NLR genes in several plant species, but these can miss structural

variants and do not reveal genomic location or arrangement. Toward the identification

of the Xo1 gene, we combined long (Nanopore) and short (Illumina) reads to generate

a high-quality genome assembly for Carolina Gold Select. We identified 529 full or

partial NLR genes and discovered, relative to the reference, an expansion of NLR

genes at the Xo1 locus. One NLR gene at Xo1 has high sequence similarity to the

cloned, functionally similar Xa1 gene. Both harbor an integrated zfBED domain and

near-identical, tandem, C-terminal repeats. Across diverse Oryzeae, we identified two

sub-clades of such NLR genes, varying in the presence of the zfBED domain and the

number of repeats. In addition to the Xo1 candidate, the genome sequence also

revealed the blast resistance gene Pi63 at the Xo1 locus. Our results show that genome

sequencing combining Nanopore and Illumina reads effectively resolves NLR gene

loci, providing context as well as the content. Our identification of an Xo1 candidate is

an important step toward mechanistic characterization, including the role(s) of the

zfBED domain. And, the Carolina Gold Select genome assembly will facilitate

identification and exploitation of other useful traits in this historically important rice

variety.

Keywords: genome sequencing, NLR gene, Xo1 locus, zfBED domain


25

Introgression of Bacterial Leaf Blight Resistance Genes into Indica

Cultivar BT7 through Marker-Assisted Backcrossing

Pham Thien Thanh, Nguyen Tri Hoan, Tang Thi Diep, Phan Thi Thanh

Field Crops Research Institute, Vietnam

Rice bacterial leaf blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is

the most serious threat to rice production in the North of Vietnam. An Indica cultivar,

BT7, is a popular rice variety with farmers of Northern Vietnam because of its good

eating quality. However, the variety is highly susceptible to bacterial blight disease.

The development of resistant cultivar has been the most effective and economical

strategy to control the disease. Three resistance genes (xa5, Xa7, Xa21) considered to

be resistance to virulent bacterial strains from Northern Vietnam were transferred

from near-isogenic line, IRBB66, using a marker-assisted backcrossing breeding

strategy, into the BT7. An advance backcross line, BT7KBL-03, of BC5F4 generation

was evaluated after inoculation with two isolates of the pathogen from the Northern

Vietnam. The combination of three genes in BT7KBL-03 line provided a wider

spectrum of resistance to the pathogen population prevalent in the region. The

morphological, yield, grain quality, and yield-contributing characteristics of

BT7KBL-03 were significantly similar to those of BT7 cultivar. The newly developed

leaf blight resistant improved line will contribute to widening cultivation area of the

highly adoptable BT7 by farmers.

Keywords: Rice, bacterial blight gene pyramiding, marker-assisted backcrossing


26

Detection and Grouping Rice Cultivars Based on the Presence of Xa-genes

in Situbondo and Jember, Indonesia

Addy, HS1,2,3*, Rasmiyana1,2, Narulita, E1,2

1Post-Graduate Program, Study Program of Magister Biotechnology. University of

Jember, Jember, Jawa Timur 68121, Indonesia. 2Division of Biology Molecule and Biotechnology, Center for Development of

Advanced Sciences and Technology, University of Jember 3Study Program of Plant Protection, Faculty of Agriculture, University of Jember

A destructive pathogen that significantly affects rice production is Xanthomonas

oryzae pv. oryzae, causing bacterial leaf blight. The use of resistant variety is the most

effective and economic technique to reduce the impact of the disease. This study aims

to analyze the genetic status of rice (Oryza sativa) related to their resistance to X.

oryzae pv. oryzae. The disease and severity of bacterial leaf blight were assessed in

the field through a diagonal random sampling method. Detection of rice resistant

genes was done by polymerase chain reaction (PCR) with eight Xa specific primers.

Its molecular trait and environmental condition were statistically analyzed to

determine the correlation between the average temperature and rain intensity against

disease incidence and disease severity. The average value of disease incidence and

severity in the generative stage were higher than in the vegetative stage. About four

groups of rice were grouped based on the presence of Xa genes sequences, mostly

Xa10 and Xa13, including a cultivar with five Xa genes. There was a weak correlation

between the presence of resistance genes with disease incidence and severity of

bacterial leaf blight. Environmental factors showed a weak correlation with disease

incidence or disease severity. Rice varieties cultivated in the regency of Jember and

Situbondo carry mostly Xa10 and Xa13 resistance genes, with a less significant role

on disease severity.

Keywords: Bacterial leaf blight, Xa genes, Xanthomonas oryzae, PCR detection, Xa

specific primers


27

Overexpression of Antisense MIR396e Confers Bacterial Blight Resistance

through Interfering Accumulation of miR396e/f-3p in Rice

Hu JX, Zhu XM, Cao YQ, Chen YT, Yu C, Yang FH, Chen HM, He CY

State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant

Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China

miRNAs, a class of 20- to 24-nucleotide-long endogenous regulatory RNAs, are

involved in the response to environmental stresses including biotic and abiotic stresses.

miRNAs inhibitors are extensively used for curing certain miRNA-mediated diseases

based on the introduction of an antisense oligonucleotide in the animal. However,

antisense miRNAs research was hardly reported in plant miRNAs. miR396 family is

very conserved in more than 50 plant species including rice. The biological functions

of miR396 in growth, development, and responses to pathogen attacks and abiotic

stress through controlling the transcription of the target GRFs (growth-regulating

factors, GRFs). Our previous work showed that miR396e/f -3p were downregulated

by bacterial infection by Xanthomonas oryzae pv. oryzae. To further elucidate the

biological functions of miR396e/f-3p, antisense MIR396e driven by 35S promoter for

constitutive expression was transformed into the rice. The transgenic rice plants

showed significant bacterial blight resistance. Further work showed that the

accumulation of mature miR396e/f-3p but not miR396e-5p was decreased

significantly in transgenic plants compared with that in wildtype. The predicted

miR396f-3p target EXO70 (exocyst complex subunit family protein) and miR396e-3p

target EH (hydrolase, alpha/beta fold family domain-containing protein) were

upregulated in antisense MIR396e transgenic plants. Transient expression assay

showed that overexpression of either EXO70 or EH in rice protoplast, induced the

transcript of defense genes such as PR1a, PR1b, PR5, and WRKY45. Therefore, these

results demonstrate that miR396e/f-3p play key regulatory roles in the response to

bacterial infection. In addition, the current study provides an example for the

application of antisense nucleotide in functional analysis of miRNAs in rice.

Keywords: miR396e; antisense MIR396e; bacterial blight of rice


28

Advances in Bacterial Blight of Rice: R Genes versus Pathogen Population

Structure in South and South-East Asia

J.S. Lore1, J. Jain1, M. S. Hunjan1, R. Kaur1, G. S. Mangat1, G. S. Laha2, N. W. Zaidi3,

O. Ricardo3, C. M. Vera Cruz3

1Punjab Agricultural University, Ludhiana, India,2Indian Institute of Rice Research,

Hyderabad, India,3International Rice Research Institute, DAPO Box 7777, Metro,

Manila, Philippines

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae [(Ishiyama),

Swing et al.1990], (Xoo) is one of the most widely distributed diseases in different

parts of Asia. BB outbreak can cause up to 50% losses depending on crop stage,

weather, location and the cultivars. The pathogen is highly variable and possesses a

number of virulence factors responsible for its pathogenicity and race differentiation.

A number of Xoo races have been identified based on near-isogenic lines in South and

South-East Asia. The majority of Xoo strains from South Asia became virulent to xa5

while the strains from South-East Asian countries like Korea, Indonesia, Philippines,

Thailand, Malaysia, and Taiwan became avirulent to this gene. Earlier, BB resistance

gene Xa21 showed moderate to a high level of resistance in most of the Asian

countries however, the gene has also been broken down by the new virulent races of

the pathogen. Till date 43 Xa/xa genes for resistance to bacterial blight have been

identified. Some of the new R genes, such as Xa23, Xa33, and Xa38 show broad-

spectrum resistance to BB in India and China. The infection of individual plants by

pathogenic organisms is governed by complex interactions between the host and

pathogen. The pathogen injects transcription activator-like effectors (TALEs) that

bind and activate host susceptibility (S) genes important for the disease. The contrast

phenotypic virulence interaction between Xoo strains and recessive R genes (xa5 and

xa13) has been reported. The pyramided lines carrying xa5+xa13+Xa21 showed

broad-spectrum resistance to the majority of the Xoo strains in South and South-East

Asia. This gene combination has been predominantly deployed in high yielding rice

cultivars. This study can explore the knowledge about the current scenario of

pathogen population structure, phenotypic virulence interaction between host and

pathogen, the effectiveness of new R genes and pyramiding of R genes in South and

South-East Asian countries for the development of high yielding rice cultivars with

durable resistance to bacterial blight.

Keywords: Bacterial blight, R gene, race, Xanthomonas oryzae pv. oryzae


29

Identification of QTLs Associated with Bacterial Leaf Blight Resistance in

Khangdan18 Cultivar

Trung Nguyen Quoc, Hai Tong Van, Chau Nguyen Thi Cam, Hien Phan Thi

Faculty of Biotechnology, Vietnam National University of Agriculture

Bacterial leaf blight (BLB) is one of the most destructive diseases in rice, especially in

a tropical country like Vietnam. Khangdan18 (KD18) is popularly grown cultivar with

the nationwide adaptation, high yield, and stable BLB resistance. In this study, the F2

population of 93 individuals from a cross between KD18 and IR24 variety was used to

identify QTLs associated with BLB resistance. Artificial inoculation method was used

with newly isolated Xanthomonas oryzae pv. oryzae X14.7. Eighty polymorphic SSR

markers distributed on 12 chromosomes were developed by using 2004 DNA markers

to survey parental genomes. Result of QTL analysis based on Composite Interval

Mapping approach with the logarithm of odds score (LOD > 3.0) showed 3 QTLs

associated with BLB resistance: qBLB1, qBLB2, and qBLB7 located on chromosome 1,

2 and 7 respectively. Applying marker-assisted selection, 18 recombinant inbred lines

were developed for further mapping and identifying potential novel BLB resistant

QTLs.

Keywords: QTL analysis, bacterial leaf blight, resistance gene, SSR marker.

.


30

Session IV: Disease Management and Breeding

Development of Bacterial Leaf Blight Resistant Hybrids for Sustainable

Rice Farming

Deo Mishra and Yog Raj

Bayer BioScience, Plot No. 13, Software Layout, Madhapur, Hyderabad-500081,

India

Rice farming community faces a lot of challenges during crop cultivation including

many biotic and abiotic stresses that cause huge economic loss annually. Among them,

bacterial leaf blight (BLB) is a serious devastating biotic stress accounting ~5%

annual loss of rice production. For this disease, an effective and long-lasting solution

has been a challenge. With the aim of having in-built protection in the crop against

BLB, we bred and developed rice hybrids by incorporating native genes for strong

resistance to protect crop yield in a sustainable way. We characterized BLB pathogen

(Xanthomonas oryzae pv. oryzae), screened rice germplasm and improvised the

breeding methodologies. This helped in understanding of pathogen population

structure and deploy effective genetics for broad-spectrum resistance suitable for

affected geographies. Developed products have been vigorously tested and

commercially launched in Asia and are providing big relief from BLB damage to rice

farming community.

Keywords: bacterial leaf blight, pathogen diversity, resistance breeding, gene

pyramiding


31

Marker-assisted Breeding for Resistance to Bacterial Leaf Blight in DT82 Rice

Variety

Vo Thi Minh Tuyen, Nguyen Thi Minh Nguyet, Pham Xuan Hoi

Agricultural Genetics Research Institute, Hanoi, Vietnam

Bacterial leaf blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of

the most destructive diseases in rice (Oryza sativa L.). The introgression of efficiently

resistance genes into high-quality rice varieties will be useful for enhancing the ability

of the durable resistance to BB disease. In this study, Marker-assisted breeding and

artificial inoculation were used to select bacterial leaf blight resistance rice lines. The

result indicated that the promising DT82 variety carried 3 BB resistance genes (Xa4,

Xa7 and Xa21) and showed high resistance to the Xoo races in the field. The new rice

variety had short growth duration (105-110 day in summer season), high quality, easy

cultivation and higher yield than the origin cultivar (Bacthom 7). DT82 variety was

approved by MARD as a potential rice variety, producing on a large scale in the

northern provinces from 2019.

Keywords: bacterial leaf blight, marker-assisted breeding, resistance gene,

Xanthomonas oryzea pv. Oryzea.


32

Profiling Endophytic Microbiome in Bacterial Blight Diseased Leaves of

Rice Identifies Bacterial Endophytes with Pathogen Antagonism and

Disease Suppression

Yang FH,1 Zhang J,1 Zhang HY,2 Ji GH,3 Zeng LX4, Chen W,2 He CY1

1State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of

Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; 2Ottawa Research & Development Centre, Agriculture and Agri-Food Canada,

Ottawa, Ontario, Canada; 3College of Plant Protection, Yunnan Agricultural University, Kunming 650201,

China; 4Plant Protection Research Institute, Guangdong Academy of Agricultural

Sciences, Guangzhou 510640, China

The endophytic microbiome plays an important role in plant health and pathogenesis;

however, little is known about its relationship with bacterial blight (BB) disease of

rice caused by Xanthomonas oryzae pv. oryzae (Xoo). The current study characterized

the compositional structure of microbial endophytic communities in the naturally

occurred BB leaves of rice, collected from Yunnan and Guangdong provinces, China,

through metabarcoding the fungal internal transcribed spacer (ITS) and bacterial 16S

rRNA gene V4 regions. Overall, Ascomycota and Basidiomycota spp. Dominated the

endophytic fungal community, while Basidiomycota spp. Were significantly less

abundant in BB leaves. At the genus level, Khuskia, Pseudopithomyces,

Leptosphaerulina, Trichoglossum, Aureobasidium, Epicoccum, Myrothecium, and

Paraphaeosphaeria were enriched in BB diseased leaves of rice. The endophytic

bacterial community of diseased leaves was significantly enriched with

Gammaproteobacteria spp., Enterobacteriaceae spp., Pantoea spp. And

Pseudomonas spp. (belonging to Proteobacteria), and Curtobacterium spp.

(belonging to Actinobacteria) relative to that in healthy leaves. Among 30 bacterial

strains of endophytes isolated from the diseased leaves, nine Pantoea strains showed

significant inhibition of Xoo. Rice leaves co-inoculated with Xoo and selected

Pantoea strains led to significantly short lesion lengths compared to those inoculated

with Xoo only, suggesting BB suppression by these Pantoea strains. Furthermore,

three Pantoea isolates showed activities in indoleacetic acid (IAA) synthesis, nitrogen

fixation, and active ACC deaminase production, indicating potential plant growth

promotion-related effects. In summary, our study revealed the community structure of

endophytic microbiome in the BB leaves of rice and characterized an array of

endophytic bacterial strains active in Xoo antagonism, BB disease suppression, and

plant growth promotion.

Keywords: bacterial blight of rice, endophyte, microbiome, Pantoea species,

biocontrol


33

Checkmating the Rice Bacterial Blight -PAU Success Story

G S Mangat, Rupinder Kaur, Jagjeet Singh Lore and Renu Khanna

Department of Plant Breeding and Genetics, Punjab Agricultural University,

Ludhiana-141004, Punjab, India

Rice is the staple food for majority of people in the world. Asia accounts for 90% of world’s

rice production. Among India’s different rice-producing states, the highest average rice

yields are obtained in Punjab. Rice was cultivated on around 3.0 million ha in Punjab, with

total paddy production of 19.9 million tons and productivity above 6.5 t/ha during Kharif

2017.

Ongoing climate change is posing a major challenge for sustainable rice production in India.

Though rice production is threatened by a number of biotic stresses, but bacterial blight

(BB) caused by Xanthomonas oryzae pv oryzae (Xoo) is a serious disease as there is no

chemical control is available against the Xoo pathogen. In view of this, deployment of host

plant resistance is the only approach for the management BB. As many as 10 pathotypes of

Xoo are prevalent in the Punjab state. Moreover, a single gene is not effective against all the

prevalent pathotypes. The quick neutralization of the resistance by the fast evolving bacteria

necessitated the augmentation of BB resistance

Recent biotechnological developments involving the use of DNA markers for efficient and

precise selection offer ways to pyramid resistance genes in desired backgrounds. In view of

the above scenario, efforts were directed towards development of rice varieties possessing

durable BB resistance (gene pyramiding), high yield, shorter growth duration and

acceptable grain quality in a sequential manner. The different BB pyramided gene

combination lines (xa5+xa13, xa5+Xa21, xa13+Xa21 and xa5+xa13+Xa21) in the

background of landmark rice cultivar PR 106 (developed under the ARBN funded

programme) were used as donors for BB resistance breeding. The segregating generations

were thoroughly phenotyped under artificial inoculation conditions using well characterized

virulent pathotypes in the field for BB and also selections were made for other

morphological traits. The systematic BB resistance breeding efforts were initiated in the late

70’s and continued later, resulted in the development and release of series of varieties which

kept the pathogen at bay for the last more than three decades. Through conjunctive use of

conventional and biotechnological techniques, bacterial blight resistance materials were

developed.

As a result of concerted and systematic breeding efforts, since 2013, five varieties of non-

Basmati rice (PR121, PR122, PR123, PR124, PR126 and PR127) and three of Basmati rice

(Punjab Basmati 3, Punjab Basmati 4 and Punjab Basmati 5) have been developed and

released in the Punjab state. All these varieties except PR126 resists the attack of all the 10

presently prevalent pathotypes of BB pathogen in the Punjab state. These varieties have

collectively covered an area of 68.5 percent in the state with PR121 being the most popular

variety covering 32 percent. All these varieties on account of shorter duration and high yield

possess higher per day productivity thereby yielding mor per unit area per unit time and per

unit of inputs and resources which is benefitting the farmers as well as the agro-ecosystem.

These have less biomass, thus paddy residue management is easier.

Key words: bacterial blight, gene pyramiding, resistance, MAS.


34

Isolation and Screening of Promising Bacteriophages to Control Bacterial

Leaf Blight Disease on Rice Caused by Xanthomonas oryzae pv. oryzae,

Nguyen Thi Thu Nga1, Nguyen Thi Truc Giang1, Tran Minh Nho1, Dan Van Bao1,

Doan Thi Kieu Tien1, Pham Van Kim1, Kaeko Kamei2, Jeffrey B. Jones3

1College of Agriculture, Can Tho University, Viet nam; 2Kyoto Institute of Technology, Japan 3Department of Plant Pathology, University of Florida, USA

Bacterial leaf blight disease caused by Xanthomonas oryzae pv. Oryzae (Xoo), is a

serious disease on rice which causes yield loss up to 50% (Mew, 1992). In the world,

using bacteriophages (phages) as biocontrol agents (BCAs) to pathogenic bacteria

have been studied broadly (Gill and Abedon, 2003; Balogh and Jones, 2003;

Obradovic et al., 2004; Iriarte et al., 2007). The aims of study survey the presence of

phage in the nature such as soil and leave to improve methods for bacteriophage

isolation and survey the parasitic efficiency to host bacterium Xoo in vitro as well as

test the effect of bacteriophage in controlling disease in the net-house and field

condition. The results show that: 1) Using the direct and enrichment method for

bacteriophage isolation, there were 107 bacteriophages isolated from 62 Xoo strains

from 6 provinces of the Mekong delta of Vietnam (i.e. An Giang, Dong Thap, Kien

Giang, Can Tho, Hau Giang, and Soc Trang); 2) Evaluation of the host range of

phages on 62 strains of Xoo, the result indicated that phages with coded ΦxaVL12,

ΦxaDT63c, ΦxaHG48b, ΦxaDT60b, ΦxaAG68a could lysis more than 45 Xoo strains,

and the bacterial strain XaAG73 revealed the most sensitive strain which is lysed by

almost isolated bacteriophages; 3) Comparison of the plaque diameters of ΦxaVL12,

ΦxaDT63c, ΦxaAG68a, ΦxaHG48b, ΦxaDT60b on the bacterial strain XaAG73,

phage ΦxaDT60b showed the largest plaque than other phages; 4) Evaluation of the

effect of bacteriophage in controlling bacterial leaf blight disease caused by Xoo in the

net house conditions, five phages (ΦxaVL12, ΦxaHG48b, ΦxaĐT60b, ΦxaĐT63c,

ΦxaAG68a) showed effect in reduction of bacterial leaf blight infection, and phage

ΦxaDT60b exposed the most effect in disease reduction by spraying phage suspension

(108 pfu/ml) on the leaf surface before and after pathogen inoculation; 5) In field

condition, comparison of the efficacy of 4 phage treatments i.e ΦxaDT60b (107

pfu/ml), ΦxaDT60b (108 pfu/ml), phage mixture (107 pfu/ml and 108 pfu/ml) with

bactericide (Starner) and control treatment, the data revealed that all phage treatments

showed efficacy in disease reduction, and the treatment ФxaDT60b (108 pfu/ml), Mix

(108 pfu/ml) expressed better disease protection and higher yield than those of the

treatment ФxaDT60b (107 pfu/ml) and Mix (107 pfu/ml), and similar to the

bacteriocide treatment Starner 20WP.

Keywords: bacterial leaf blight, bacteriophage, rice, Xanthomonas oryzae pv. Oryzae


35

Characterization of Bacteriophages Infecting Xanthomonas oryzae pv.

oryzae

Rejeki, Desi1,2, Addy, Hardian Susilo2,3, Narulita, Erlia2,4

1Graduate School of Biotechnology, University of Jember 2Center for Development of Advanced Sciences and Technology (CDAST), University

of Jember 3Department of Plant Protection. Faculty of Agriculture, University of Jember 4Department of Biology Education, Faculty of Teacher Training and Education,

University of Jember

Bacterial leaf blight (BLB) is a disease of rice in rice-producing countries including

Indonesia and attack rice in all stages of growth. The BLB is caused by Xanthomonas

oryzae pv. oryzae (Xoo) with the symptoms of grayish color and slightly wet on both

sides of the leaf and part of the side. In the advanced, crop production will be

decreased up to 50-70%. Recently, the effective efforts to overcome the problem by

using resistant varieties, antibiotics, sanitation, and antagonistic combinations;

however, the ability of the pathogen to forms new virulent pathotypes is noteworthy.

An alternative by utilizing bacteriophages as biological control agents could be used

because of their specific characteristics to their bacterial hosts. This research aimed to

obtain some information about the characterization of bacteriophage particles and

bacteriophage biological characters. The result showed that two bacteriophages had

been isolated from soil in Arjasa Jember and soil in Gadingan Situbondo, namely

phage XooAT (from Arjasa), and phage XooGT (from Gadingan) with similar plaques

morphology. The two phage isolates were inactivated at 80 ºC, and stable at pH within

the range of 6 to 8. The phage XooAT has a genome size of approximately 39 kb,

while phage XooGT had a genome size 38 kb and were differentiated into some types

by their EcoRV and XbaI restriction fragment patterns. According to the nuclease

pattern of nucleic acid, both phages are double stranded deoxyribose nucleic acid

(dsDNA) viruses. Moreover, protein profile on SDS-PAGE showed that similar

protein bands were appear on polyacrylamide gel. Phage biocontrol in vitro assay

showed that both phages significantly reduced the growth of BLB pathogen in the

liquid culture at MOIs between 0,01 and 10 indicating that both phages potentially,

are able to biological control BLB disease in rice.

Keywords: bacteriophage, Xanthomonas oryzae pv. oryzae, bacterial leaf blight,

phage therapy


36

Biological Control of Bacterial Leaf Blight of Rice by Bacillus Strains in the

Mekong Delta: Current Status and Future Prospects

Tran Vu Phen1, Tsutomu Arie2, Huynh Van Nghi1, Nguyen Chi Thuc1,

Do Van Chung1, Nguyen Huu Thinh1, Tran Bao Ngan1

1Department of Plant Protection, College of Agriculture, Can Tho University, Vietnam 2Tokyo University of Agriculture and Technology, Japan

Bacterial leaf blight (BLB) of rice caused by Xanthomonas oryzae pv. Oryzae (Xoo) is

among the most devastating rice diseases that occur globally, including the Mekong

Delta of Vietnam. Farmers who are well aware of the harmful effects of pesticides still

heavily rely on plant protection chemicals. Among many efforts to manage this

disease, biological control using beneficial bacteria, especially Bacillus spp. Has been

considered as a prospective tool.

During 2012-2018, the research results at Can Tho University have recorded some

promising Bacillus strains, belong to B. subtilis, B. Amyloliquefaciens, Brevibacillus

brevis, ... which have been showed high antagonistic potential in vitro (radius of

inhibition zone 11-13.5 mm) and effective in suppressing BLB under net house

conditions or farm level field plots (BLB disease suppression 60-70%, equivalent to

common chemical bactericides, i.e. oxolinic acid, pronopol, at recommended

concentration). The promising Bacillus strains have been mass multiplied and

processed to powder (talc based substrate) or liquid (DSM-PVP) formulations. Shelf-

life stability tests of formulated bacteria were performed under room temperature

storage conditions showed that Bacillus spp. Remained stable over the period of four

to six months (5x108 cfu/ g or ml). The formulation was then tested against Xoo in in

vitro or net house conditions and the efficacy results revealed that the formulation

process did not affect the biocontrol potential of these strains. The evaluation of

formulations against BLB under field conditions showed that when applying leaf

sprays, 3 day intervals from 5% heading (seven sprays in total) resulted in reducing

bacterial leaf blight severity 63.40-73.48 %, equal to that of farmers’ practices

(Starner 20WP, 1.25‰, four sprays) and increase of grain yield over non-inoculated

plots.

Bacillus spp. Which is known to own diverse antagonistic mechanisms against Xoo,

can survive unfavourable conditions as endospores and are expected to be long-term

survival in the natural environment after being applied. The bioformulation based on

Bacillus spp. Can be stored long-term and maintain stable effectiveness. Additionally,

the suitability of technology should be taken into account to develop a stable and

effective and Bacillus spp. Should be a potential biocontrol agent for

commercialization to eco-friendly manage the BLB in the near future in the Mekong

Delta.

Keywords: Bacillus, bacterial leaf blight, biocontrol, bioformulation


37

Eco-friendly Management of Bacterial Leaf Blight Disease of Rice in

Kuttanadu

Zacharia, R.M and Yohannan, A

Rice Research Station, Moncompu, Alappuzha, Kerala, India

The bacterial disease of rice caused by Xanthomonas oryzae p.v. oryzae remains as a

major production constraint causing a grain loss of 6-60%, in the below mean sea level

tracts of Kuttanadu, the rice bowl of Kerala state, India. This disease is known to occur in

an epiphytotic proportion almost every year in the additional crop season from June to

August due to the conducive weather condition with an annual mean temperature of

26.6C, annual rainfall of 3000 mm and mean relative humidity of above 85%. Annual

flooding also favours its occurrence.

Development of resistant strains of the pathogen is causing serious problems in

formulating full proof control. The policy of the State government to promote organic

cultivation of all crops is not permitting cultivation of transgenic crops. Improper and

untimely use of antibiotics like streptocycline seems to be less effective under field

conditions. It has become necessary to search an option for antibiotics for BLB control.

Mary (1996) reported the effectiveness of a curative spray with cowdung supernatant @

20g/l. Thus, a study was framed using several organic solutions, chemicals with

sterilizing effect, plant extracts, homoeopathic drugs with bactericidal properties.

In vitro studies were conducted using the agar diffusion method. Treatments showing

higher zone of inhibition were selected for the first in vivo pot culture study under CRD.

Highly susceptible variety MO-4 (Bhadra) that gave a score of 9 under artificial

inoculation was selected as the variety. Leaf clipping method was used for artificial

inoculation. Common checks were maintained with Strepto G (recommended control) and

Streptomycine sulphate (check). Two post inoculation sprays were given at 42 DAS and

62 DAS for the first experiment. In the second experiment with 16 treatments, one pre

inoculation spray and a post-inoculation spray were given at 38 DAS and 60 DAS.

Disease severity and yield were recorded at 120 DAS.

The treatments were found to be significantly different for both experiments. For the first

one, Thuja 30P (homeopathic drug) gave the highest disease control. This was on par

with Panchagavya (organic solution), potassium permanganate 20% and Pseudomonas+

cowdung supernatant. In the case of yield, the first two treatments were on par with

potassium permanganate 20%. In the nutrient analysis of harvested straw boron content

was increased in all the treatments and was indirectly related to chaffness of grains. In the

second experiment, disease severity was found to be significantly reduced in all the

treatments. Thuja 30P, potassium permanganate 20%, neem leaf extract, Pseudomonas,

Pseudomonas+ cowdung supernatant, Panchagavya, Badi Aga, cowdung supernatant

were found to be effective in reducing disease severity. Thuja gave the highest yield.

Treatments like Panchagavya, potassium permanganate 20%, Pseudomonas,

Pseudomonas+ cowdung supernatant, Asafoetida, Jeevamrutham also gave a good yield.

Panchagavya (organic solution) and Thuja 30P (homeopathic drug) were found to be

promising for reducing the disease severity of BLB and for getting higher yield in rice.

Keywords: Bacterial, disease, rice


38

Defense Biochemical Alterations in Rice Leaves on Induced Resistance

against Xanthomonas oryzae pv. oryzae

Toan Le Thanh1,2, Kanjana Thamanu3, Hideo Nakashita4, Sopone Wongkaew2 and

Natthiya Buensanteai2

1Department of Crop Protection, College of Agriculture, Can Tho University, Viet

Nam; 2School of Crop Production Technology, Institute of Agricultural Technology,

Suranaree University of Technology, Thailand; 3Synchrotron Light Research Institute, Thailand; 4Faculty of Bioscience, Fukui Prefectural University, Japan

Bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. Oryzae (Xoo)

is the most frequent disease in rice fields. BLB management is mainly focused on

methods of using agrochemicals and resistant cultivars to reduce the initial inoculum

and enhance rice health. Induced resistance, based on the increased expression of

genes in rice plants, could elicit natural defense mechanism in rice. The induced rice is

able to resist an attack of virulent pathogens by enhancing an array of rapidly

expressed defenses upon infection. The elicitors including SA, ascorbic acid (AA),

benzo (1,2,3)-thiadiazole-7-carbothionic acid S-methyl ester or acibenzolar-S- methyl

(ASM), chitosan, BTH, ZnSO4.7H20, soluble silicon have been extensively evaluated

against several plant diseases. The induced resistance of rice against Xoo by priming

with exogenous 1,2-Benzisothiazol-3 (2H)-one 1,1-dioxide (BIT) has not yet been

characterized. Therefore, the objective of the study was to characterize the defense

responses of rice plants against LB after treatment with exogenous BIT at a

concentration of 2 mM and challenge inoculation with Xoo by monitoring

biochemical changes associated with plant defense mechanisms. The experiment was

conducted with a completely randomized design, five replications. Rice seeds cv.

KDML105 were soaked thoroughly with 100 ml of the solution of BIT at a

concentration of 2 mM. Rice seeds treated were planted in 35 cm-plastic pots

containing soil. The rice plants were further treated by foliar sprays with the solution

of 2 mM BIT until it ran off, at 15, 30 and 45 days after planting (DAP). Six matured

leaves of fifty-day-old rice plants per one pot were randomly chosen and inoculated

by cutting leaf tips, approximately 3 cm from the leaf tip, and dipped into a Xoo

suspension at the density of 1x108 cfu ml−1. Leaf samples including above or below

leaf were collected at 7 DAI and put into an oven at 60oC for 2-3 days, then ground

into fine powder by mortars and pestles. Equal weights of powder samples were taken


39

and analyzed by ATR-Fourier transform infrared (ATR-FTIR) spectroscopy. The

results showed that BIT-induced rice leaves had many intense peaks which

represented defensive carbohydrates, proteins, and lipids. At leaves above the Xoo-

inoculated leaf, exogenous BIT treatment had importantly spectral shifts than those of

BIT-non treated control at the peaks of lipid and protein, such as 2920, 2851, 1736

cm-1, and the structural change of amide I from alpha helix type at the peak of 1655

cm-1 to β-sheet type at 1636 cm-1. At rice leaves below the Xoo-inoculated leaf, its

Fourier transform infrared peak assignments of the BIT-induced treatment had

significantly spectral peaks than those of the control treatment at some vibrational

peaks of lipid and carbohydrate, such as 2920, 2851, 1319, 1103 and 1040 cm-1. Three

vibrational peaks such as 1319, 1103 and 1040 cm-1 could be used as biomarkers of

induced resistance in rice. In this study, the elicitor of BIT reduced leaf blight severity

in rice plants by approximately 34.82%.

Keywords: BIT, leaf blight, Fourier transform infrared spectroscopy, and induced

resistance.


40

Session V: Molecular Interaction Between Host and X. oryzae pv. oryzae

Xanthomonas oryzae – Triggered Production of Atypical Rice Small RNAs

During Infection

Reshetnyak G.*1, Jacobs J.*1-2, Auguy F.1, Claude L.1, Sciallano C.1, Medina C.1,

Perez-Quintero A.1, Thomas E.1 , Rivas JC.1, Bogdanove A.3, Dievart A.4 , Koebnik

R.1, Szurek B.1, Brugidou C.1, Lacombe S.1, Cunnac S.1

1IRD,CIRAD, Univ Montpellier, IPME, Montpellier, France 2Department of Plant Pathology, Infectious Disease Institute, Ohio State University,

Columbus, OH, United States. 3Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant

Science, Cornell University, Ithaca, NY, United States 4CIRAD, UMR AGAP, Montpellier, France

Eukaryotic regulatory small RNAs (sRNA) range from 20 to 24 nucleotides and are

ubiquitous in plants. As mediators of transcriptional and post-transcriptional gene

silencing, they play are important in regulating growth, development and stress

responses. In the plant cell, sRNAs are mostly endogenous but can derive from viral

sequences or be delivered by interacting organisms. sRNA biogenesis begins with the

cleavage of double-stranded RNA precursors by a dicer-like enzyme (DCL). The

resulting sRNA duplexes are then protected from degradation by HEN1-mediated

methylation, and the mature guide sRNA strand is incorporated into the RNA-induced

silencing complex (RISC). RISC targets complementary nucleotides to dampen gene

expression. Early insight on sRNAs in plants revealed their role in antiviral defense

and they are now extensively studied in response to diverse pathogens. Here we

describe a novel class of sRNA in rice (Oryza sativa) associated with foliar diseases

caused by Xanthomonas oryzae pathovars. Analysis of our high-throughput sRNA

sequencing data suggests that Xanthomonas-induced small RNAs (xisRNAs) possess

features of regulatory sRNA and may target genes involved in plant immune signaling

or sRNA production. xisRNAs biogenesis is still enigmatic but we showed that it

depends on some canonical sRNA pathways components. In addition, transcription of

protein-coding loci overlapping the genomic sequences of xisRNAs is required for

their accumulation. Our results further indicate that X. oryzae uses its virulence

arsenal of type III effectors for maximal xisRNA accumulation. Finally, we will report

on our efforts to address the significance of these xisRNA during disease.

Keywords: small RNAs, RNA silencing, RLCK, Xanthomonas oryzae, rice


41

The RpoN2-PilRX System Regulates Type VI Pilus-dependent Motility and

is Required for Virulence in Xanthomonas oryzae pv. Oryzae

Yu C1, Yang C-H2, He CY1


Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; 2Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee,

WI 53211, USA

Type IV pili (T4P), a special class of bacterial surface filaments plays a crucial role in

bacterial interactions with host and pathogenesis, surface adhesion, motility, and

biofilm formation. The T4P secretion machinery is made up of 4 subcomplexes: (i)

the outer membrane subcomplex formed by the dodecameric ring of PilQ and the pilot

in PilF, (ii) the inner membrane platform, made up of PilC, PilM, PilN, PilO and PilP,

(iii) the ATPases PilB, PilT and PilU, and (iv) the pilus filament, a polymer of the

major pilin, PilA, and minor pilins. The genomic sequence of Xanthomonas oryzae pv.

oryzae (Xoo) strain PXO99A showed 13 regulons containing 26 genes (PilAX-PilZX)

coding for T4P structural components and putative regulators. How the T4P system is

regulated and how it is related to bacterial pathogenesis are not well understood. Our

previous studies showed that alternative σ54 RpoN2 worked together with its

transcriptional activator FleQ to regulate flagellar motility through affecting flagellar

gene transcription, whereas RpoN2 regulated bacterial virulence in rice through a

FleQ-independent manner. In this study, the yeast two-hybrid (Y2H) and GST pull-

down assays revealed that RpoN2 directly and specifically interacted with PilRX, a

homolog of the response regulator PilR of the two-component system (TCS) PilS/PilR.

A consensus RpoN2 binding sequence NNGGN10GCNN was identified in the

promoter sequences of 13 T4P gene transcriptional units that were determined by RT-

PCR analysis. EMSA assays confirmed direct binding of RpoN2 to the promoters of

pilAX, pilCX and pilRX. Each gene deletion in pilAX, pilCX, and pilRX resulted in

significantly reduced sliding and swimming motility and virulence in rice. Taken

together, the findings from the current study suggest that RpoN2-PilRX system

regulates bacterial motility and pathogenesis which might be via regulating T4P gene

transcription in Xoo.

Keywords: σ54, PilRX, motility, type VI pilus, virulence, transcriptional regulation


42

Cyclic Di-GMP Signaling Regulation of Virulence in Xanthomonas oryzae

pv. oryzae

Yang FH1, Xue DR1, Tian F1, Hutchin W2, Yang C-H3, He CY1


Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; 2Department of Biology, Carthage College, Kenosha, WI 53140-1994, USA; 3Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee,

WI 53211, USA

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight of rice, one of the

most devastating bacterial diseases of this staple crop worldwide. Xoo produces a

range of virulence factors to facilitate its pathogenesis in rice, however, the regulatory

mechanisms of Xoo virulence expression have been not fully elucidated. Further

insight into signaling pathways involved in regulation of virulence will contribute to

the understanding of Xoo pathogenesis, and effectively allow the development of

prevention strategies and control of pathogenic infection in rice. Our recent studies

showed that virulence factor production in this pathogen was mediated by the

regulation of the second messenger nucleotide cyclic dimeric guanosine

monophosphate (c-di-GMP). The genome encodes a set of GGDEF, EAL, HD-GYP,

and PilZ domain containing proteins with diverse signal sensory domains for c-di-

GMP synthesis, hydrolysis, and binding. Bioinformatic, genetic, and biochemical

analysis has identified an array of diguanylate cyclases (DGCs) and

phosphodiesterases (PDEs), as well as degenerate GGDEF/EAL and PilZ domain

proteins, along with a transcription regulator. These signaling components have been

characterized to regulate various bacterial cellular processes, such as virulence,

exopolysaccharide (EPS) production, biofilm formation, and motility, at

transcriptional, post-translational, and protein-protein interaction levels. In this present

review, we summarized the findings that have revealed the importance and complexity

of c-di-GMP signaling in regulating bacterial virulence in Xoo, highlighting key

signal elements also found in other close Xanthomonas species, also discussing the

possible existence of a complicated multifactorial network between the DGCs, PDEs,

receptors and effectors. These findings lay the groundwork for future experimentation

to further elucidate c-di-GMP regulatory circuits involved in the regulation of

bacterial pathogenesis.

Keywords: c-di-GMP; signaling; regulation; virulence; Xanthomonas species


43

Combined Transcriptome and Proteome Analysis of the Pathogenicity-

Activated Xanthomonas oryzae pv. oryzae

Kim S1, Kim JG1, and Kang LW2

1Genomics Division, National Institute of Agricultural Sciences, Rural Development

Administration (RDA), Jeonju 03016, Republic of Korea; 2Department of Biological Sciences, Konkuk University, 120 Neungdong-ro,

Gwangjin-gu, Seoul 05029, Republic of Korea

Our group developed the in vitro assay system to study time-resolved genome-wide

gene expression of Xoo. The in vitro assay system was used for the combined

transcriptome and proteome study of Xoo upon the pathogenicity activation via the

initial interactions with rice leaf extract (RLX). Genome-wide gene expression of Xoo

upon pathogenicity activation was systematically studied in both transcription and

translation at multiple time points, which provides a useful tool to study pathogenic

gene expression at the initial stage of pathogen-host interaction. Chemotaxis and

flagella biosynthesis-related genes showed simultaneous expression of mRNA and

protein, in which transcription and translation are tightly coupled. Genes related to

inorganic ion transport and metabolism including iron and phosphate showed 30 – 120

min delayed translation after transcription. Although transcription and translation

could occur simultaneously in bacteria, genes of different functional categories

showed variable time gaps between the peaks of transcriptional and translational gene

expression.

Keywords: plant–pathogen interactions, proteomics, transcriptome, time-resolved

genome-wide gene expression, Xanthomonas oryzae pv. oryzae, pathogenicity


44

Xanthomonas oryzae pv. oryzae T3SS-effector XopF Interacts with Multiple

Rice Targets to Subvert the Immune Responses during Bacterial Blight

Development

Kalyan K. Mondal and Aditya Kulshreshtha

Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi

110012, India

Bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo), severely affects rice

production globally. Xoo depends on effector proteins for its successful proliferation

into the rice plants. These effectors are secreted directly into the rice cells through a

type 3 secretion system (T3SS). We previously documented that XopF effector is

essential for bacterial virulence, spread inside the plant and suppresses the rice PTI.

Now it is important to know the possible interactor(s) for the XopF in rice. The

present study is thus aimed at searching the rice interactor(s) for XopF employing

yeast two-hybrid (Y2H) system. The full-length xopF gene (accession: KF939317)

was PCR amplified and subsequently cloned into yeast bait vector in fusion with

GAL4 DNA binding domain. Before library screening, we verified the non-toxic and

non-autoactivating nature of XopF on the nutritional dropout medium. In order to

develop the cDNA library, total RNA was extracted from healthy and infiltrated (with

Xoo race 4) rice leaves (cv pusa basmati 1) and pooled together before cDNA

preparation. The cDNA library was cloned into yeast prey vector pGADT7 in fusion

with the GAL4 DNA-activation domain. The library was transformed into yeast Y187

strain. The transformed library was screened using XopF as bait. The mated positive

colonies were selected, and the serial dilution was performed on QDO medium. The

cDNA library fragments from the positive colonies were PCR amplified, cloned and

sequenced. Based on sequence data, we identified two key interactors, namely

chloroplastic photosystem I subunit V (Accession No. XP_015611871) and

cyclophilin II (Accession No. GQ848065). Both these interactors are known to play a

role in the suppression of immune responses in plant. XopF targets the plant

photosystem I supercomplex (with light-harvesting complexes I and II) to interfere

with the normal photosynthesis leading to breakdown of resistance. Whereas, plant

cyclophilin is a well-known target for bacterial pathogens to suppress plant immunity.

The present study is thus concluded that XopF targets multiple interactors with the

primary aim to subvert the immune responses of plants through suppressing

photosynthate via photosystem I as well as through compromised immune protection

system like cyclophilin in plants. This insight will be useful in exploring strategies for

disease resistance.

Keywords: Xanthomonas, T3SS, XopF, effector


45

Xylose-dependent hrp Gene Expression in Xanthomonas oryzae pv. oryzae

Tsuge, S. and Ikawa, Y.

Kyoto Prefectural University, Kyoto, Japan

hrp genes encoding components of the type III secretion system are indispensable for

virulence of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight

of rice. Expression of hrp genes is induced only in plants or certain nutrient-poor

media, so called hrp-inducing media. The expression of hrp genes is regulated by two

key hrp regulators, HrpG and HrpX; HrpG, predicted to be an OmpR-type response

regulator of a two-component signal transduction system, regulates hrpX, and HrpX, a

member of an AraC-type transcriptional activator family, regulates other hrp genes.

Besides them, several regulators or regulatory cascades that are involved in the

regulation of hrp genes have been reported, though the whole feature of the regulatory

network still remain unclear. We found that hrp gene expression of X. oryzae pv.

oryzae is specifically induced when xylose is added in the hrp-inducing medium, and

that the second key hrp regulator HrpX abundantly accumulated only in the presence

of xylose, which causes the induction of HrpX-regulated hrp gene expression,

although hrpX expression is independent on sugar source. Random transposon

mutagenesis revealed that a LacI-type transcriptional repressor XylR is involved in the

negative regulation of hrp gene expression. In the mutant lacking xylR HrpX

accumulation and the expression of hrp genes were highly induced even under the

xylose-free condition. XylR also negatively regulated xylan/xylose metabolism-

related genes by binding to the cis element located upstream of the target genes, and

the negative regulation was cancelled in the presence of xylose or in the absence of

XylR. The mutant deficient in xylose isomerase, which converts xylose to xylulose in

the first step of the xylose metabolism, showed similar hrp gene expression to the wild

type in the medium containing xylose, suggesting that xylose, not its metabolites,

functions as the substrate to inactivate XylR. Furthermore, the introduction of amino

acid substitution in the substrate-binding domain of XylR caused less hrp gene

expression even in the presence of xylose, and the virulence of the mutant in rice

plants was weaker than that of the wild type. The results suggest that, in X. oryzae pv.

oryzae, expression of hrp genes and xylan/xylose metabolism-related genes are

concomitantly and negatively regulated by XylR, and that, by inactivating XylR,

xylose plays an important role in virulence of the bacterium.

Keywords: Xanthomonas oryzae pv. oryzae, hrp, type III secretion system,

transcriptional regulator, xylose


46

Session VI: Integrative Genomics, Proteomics – Effectors, Epigenetics

of X. oryzae pv. oryzae

Bioinformatic Approaches to Uncover Genetic Acquisitions Associated

with Epidemic Populations of Xanthomonas oryzae pv. oryzae

Alvaro L Perez-Quintero1, Rex Steele1, Jonathan Jacobs,1,2 Jan Leach1

1.Department of Bioagricultural Sciences and Pest Management, Colorado State

University, Fort Collins, CO, United States

2.Department of Plant Pathology, Infectious Disease Institute, Ohio State University,

Columbus, OH, United States

The sudden appearance and rapid spread of pathogen populations can be associated to

changes in environmental conditions or to exposures to susceptible hosts (as when

introduced to a new geographical region). However, often, these spreads are also

associated to genetic changes in the population: mutation or acquisition of new

genetic features, that confer the population a fitness advantage. Currently, bacterial

genomic data is being generated at exponential proportions, and much of it is

underexploited. We are developing strategies to integrate methods for genomic

analyses in a way that given a set of bacterial genomes and any trait of interest, a user

can obtain possible genes or genomic regions associated to said trait. We used this

approach to study a population of Xanthomonas oryzae pv oryzae (Xoo) obtained from

field experiments where breakdown of resistance mediated by the R genes Xa7 and

Xa1 was shown. Particularly, some strains of race 9b were able to infect Xa7-carrying

plants without losing the cognate avrXa7 gene. We applied our genome association

pipeline to a set of newly sequenced genomes from this population as well as all

available Xoo genomes, thus identifying candidate genes associated with resistance

breakdown, including a candidate interfering TAL effector. We are currently applying

this pipeline to other emerging and epidemic populations of Xanthomonas.

Keywords: Xanthomonas, Xa gene, TAL effector, genomic analyses


47

BDSF is the Predominant In-Planta Quorum-Sensing Signal Used During

Xanthomonas campestris Infection and Pathogenesis in Chinese Cabbage

Diab Abdelgader Abdeen, Cao Xue-Qiang, Song Kai, Zhou Lian, He Ya-Wen

State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of

Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai

Jiao Tong University, Shanghai 200240, China

Molecules of the diffusible signal factor (DSF)-family are a class of quorum sensing (QS)

signals used by diverse Gram-negative bacterial pathogens. Studies during the last two

decades have outlined the structural, signaling, biosynthetic pathway and natural turnover

properties of DSF-family signals in the phytopathogen Xanthomonas campestris pv.

campestris (Xcc). However, all of the DSF-family signals characterized from Xcc to date

were derived from in vitro laboratory-based cell culture. The in planta QS signal used

during Xcc infection and pathogenesis remains to be elucidated. To answer this question, we

presented the following results in this study: (1) We first utilized XYS medium

supplemented with cabbage hydrolysate to mimic Xcc growth conditions in planta. We

found that the dominant signal produced in these conditions was BDSF, a member of DSF-

family signals. (2) We then examined the effects of various plant-derived compounds (15

non-branched-chain amino acids, 3 branched-chain α-ketoacids, 3 carboxylic acids, 5 plant-

derived organic acids, 6 plant hormones, and 8 plant-derived phenolic compounds) on the

biosynthesis of DSF-family signals in vitro. Several compounds were found to promote

BDSF biosynthesis. (3) The further Western blotting analysis showed that plant hormone

ABA and trans-2 hydroxycinnamic acid significantly affected the expression of BDSF

synthase RpfF. The other compounds probably are used as a carbon source to promote

BDSF biosynthesis. (4) We established an Xcc ΔrpfB-Chinese cabbage infection model and

a UPLC-TOF-MS-based assay optimized for DSF-family signals. We found that BDSF

comprised more than 70% of the DSF-family signals present in infected cabbage tissue.

Further analysis showed that BDSF is functional quorum sensing signal in Xcc. BDSF at a

concentration of 2.0 μM induced both protease activity and engXCA expression. The

induction is dependent on the signal receptor RpfC.

This is the first report to directly show that BDSF is the major in planta QS signal used

during the Xanthomonas infection process. It provides a better understanding of the

molecular interactions between Xcc and its cruciferous hosts during infection, and also

identifies the logical target for designing strategies to counteract BDSF signaling and thus

infection.

Keywords: Xanthomonas, quorum sensing, BDSF.


48

Getting into the Weeds: How Monitoring Xanthomonas Species Outside the

Paddy can Inform Crop Management and Our Understanding of Pathogen

Evolution

Lang, J.M.1,2, Pérez-Quintero, A.L.1,2, Koebnik, R.2, DuCharme, E.1, Sarra, S.3,

Doucoure, H.4, Keita, I.4, Ziegle, J.5, Jacobs, J.M.1,2,6, Oliva, R.7, Koita, O.4, Szurek,

B.2, Verdier, V.1,2**, Leach, J.E.1

1Department of Bioagricultural Sciences and Pest Management, Colorado State

University, Fort Collins, CO, USA; 2IRD, Cirad, Université de Montpellier, IPME,

Montpellier, France; 3Centre Régional de Recherche Agronomique de Niono, Institut

d’Economie Rural (IER), Bamako, Mali; 4Laboratoire de Biologie Moléculaire

Appliquée, Université des Sciences Techniques et Technologiques, Bamako, Mali; 5Pacific Biosciences, Menlo Park, CA; 6Department of Plant Pathology, Infectious

Disease Institute, Ohio State University, Columbus, OH, USA; 7International Rice

Research Institute, Los Baños, Philippines.

Xanthomonas oryzae (Xo) are globally important rice pathogens. Virulent lineages

from Africa and Asia and less virulent strains from the US have been well

characterized. X. campestris pv. leersiae (Xcl), first described in 1957, causes bacterial

streak on the perennial grass, Leersia hexandra, and is a close relative of Xo. L.

hexandra, a member of the Poaceae, is highly similar to rice phylogenetically, is

globally ubiquitous around rice paddies, and is a reservoir of pathogenic Xo. We used

long read, single molecule, real time (SMRT) genome sequences of five strains of Xcl

from Burkina Faso, China, Mali and Uganda to determine the genetic relatedness of

this organism with Xo. Novel Transcription Activator-Like Effectors (TALEs) were

discovered in all five strains of Xcl. Predicted TALE target sequences were identified

in the L. perrieri genome and compared to rice susceptibility gene homologs.

Pathogenicity screening on L. hexandra and diverse rice cultivars confirmed that Xcl

are able to colonize rice and produce weak but not progressive symptoms. Overall,

based on average nucleotide identity, type III effector repertoires and disease

phenotype, we renamed Xcl to X. oryzae pv. leersiae (Xol) and propose using this

parallel system to improve understanding of the evolution of bacterial pathogenicity in

rice agroecosystems.

Keywords: Xanthomonas oryzae, Transcription Activator-Like Effectors (TALEs),

agroecosystem, cutgrass, rice


49

Session VII: Biotech and Genome/Gene Editing

OsERF#123, a New Susceptibility Gene for Bacterial Blight of Rice

Hutin M1,3, Tran TT1, Belanto JJ2, Wang L3, Perez-Quintero AL14, Thomas E1,

Willmann MR3, Voytas DF2, Szurek B1, Bogdanove AJ2

1UMR IPME, IRD-CIRAD-Université Montpellier, Montpellier, France 2Department of Genetics, Cell Biology & Development and Center for Genome

Engineering, University of Minnesota, Mineapolis, United States of America 3Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant

Science, Cornell University, Ithaca, New York, United States of America 4Department of Bioagricultural Sciences and Pest Management, Colorado State

University, Fort Collins, CO, United States

Bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is a devastating

disease of rice, a crop that feeds more than half of the world’s population. Xoo

virulence critically depends on the transcription activator-like effector (TALE)-

dependent activation of specific host genes called susceptibility (S) genes. The number

of TALEs per strain varies from 9 to 16, with African strains, which form a distinct

genetic lineage, typically having fewer TALEs than Asian strains. While one or two

TALEs per strain generally act as major virulence factors, the relative contributions of

the other TALEs to Xoo pathogenicity is unclear. We sequenced the entire genomes

and compared the TALE repertoires of three African Xoo strains. We assessed the

individual contribution to pathogen virulence of 13 TALE variants represented in the

three strains and identified TalB as a new, major virulence factor. RNA profiling and

in silico prediction of TalB binding sites in rice revealed OsTFX1, a bZIP

transcription factor previously identified as a bacterial blight S gene, and OsERF#123,

which encodes a subgroup Ixc AP2/ERF transcription factor, as candidate targets.

Activation of OsERF#123 using gene-specific designer TALEs restored virulence to a

talB knockout strain, confirming OsERF#123 as a new bacterial blight S gene. We

have generated and are currently characterizing OsERF#123 promoter-edited and

OsERF#123 CDS deletion lines to further probe the role of OsERF#123 in

susceptibility and to understand its function in other contexts.

Keywords: Susceptibility genes, TAL effectors, Resistance, African Xoo


50

Legal Framework for Genome Editing Approaches in Agricultural

Development

Sarah M Schmidt1, Boris Szurek2, Bing Yang3, Frank White4, Ricardo Oliva5, Wolf

Frommer1

1Heinrich Heine University, Düsseldorf, Germany, 2 Institut de Recherche pour le

Développment (IRD), Montpellier, France, 3 University of Missouri, St. Louis, US, 4

University of Florida, US, 5 International Rice Research Institute (IRRI), Los Banos,

Philippines

Genome editing, and especially CRISPR technology, are said to democratize and

revolutionize agricultural research. Many people believe in the potential benefits of

genome editing for food security. But what does it take to develop a genome edited

crop? Which legal requirements need to be followed? And what is the legal

framework for releasing a genome edited crops in countries in America, Europe, Asia

and Africa? Within the Healthy Crops research consortium, we are developing rice

varieties that are resistant against Bacterial Blight by genome-editing of the SWEET

promoters for smallholder farmers in Asia and Africa. One difficulty for developing

resistant crops using genome editing approaches is IP (Intellectual Property). I will

discuss our approach to obtain Freedom to Operate, that is to use patented technology,

within a humanitarian research project. Furthermore, I will present the regulatory

strategy for our research-for-development project as well as an overview of the current

legal frameworks for genome-editing in the EU, US, Australia, Argentina, Colombia,

Japan and other countries. Finally, I will provide insights into the ongoing decision

process in several Asian and African countries and discuss the difficulties of creating

a globally harmonized legislation on genome editing.

Keywords: Genome editing, CRISPR, bacterial blight, resistance, agriculture for

development


51

Poster Presentations’ Abstracts

P01: Characterization of Xanthomonas oryzae Strains Causing Rice

Bacterial Diseases in Senegal: Towards the Identification of Genetic

Sources of Resistance to BLB and BLS

Hamidou Tall1,3, Kandioura Noba2, Boris Szurek3, Mathilde Hutin3 , Sébastien

Cunnac3, Valérie Verdier3

1Institut Sénégalais de Recherches Agricoles (ISRA), Bel Air, Dakar Sénégal 2 Département de Biologie végétale, Université Cheikh Anta DIOP de Dakar 3IRD, Cirad, Univ Montpellier, IPME, Montpellier, France

Bacterial diseases limit rice yield in Africa and thus threaten food security. Bacterial

Leaf Blight (BB) and Bacterial Leaf Streak (BLB) caused by Xanthomonas oryzae pv.

oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), respectively, were

reported once in Senegal in the eighties but no isolate was collected. Resistance

breeding depends on adequate knowledge of the genetic diversity of pathogen

populations. The choice of BB and BLS resistance gene(s) should be made based

upon their effectiveness against the prevalent races of Xoo and Xoc in the region. As

no strains were collected in Senegal so far, no strategy has been pursued to control the

diseases.

To confirm the presence of X. oryzae in Senegal, we assessed the prevalence of BB

and BLS in different regions of the country. The main areas of domestic rice

production were surveyed between 2014 and 2016. Symptomatic leaf samples were

collected in the field and analyzed. Following bacterial isolation, a PCR multiplex

scheme confirmed the presence of Xoo and Xoc in different sites of each region. A set

of IRBB lines was used to identifying effective BB resistance genes and characterize

the races of Xoo in Senegal. We also evaluated the virulence of strains of Xoc and

Xoo on popular rice accessions to evaluate their level of resistance to these two

pathovars and their impact on the yield of these varieties. Finally, to potentially

connect Transcription Activator-Like Effector genes with pathogenicity/host range,

we profiled their genomic repertoire in Senegalese of Xoo and Xoc strains.

The use of rice cultivars with introgressed disease resistance I genes is currently the

best way to control BB disease with minimal environmental effects and cost. No rice

resistance gene has been reported to control BLS worldwide. Our results will

contribute to a more rational deployment of sources of genetic resistance to BB and

BLS in Senegal.

Keywords: Report, characterization, Senegal, bacterial diseases, rice, Xanthomonas

oryzae, control strategies


52

P02: Pursuing Durable, Broad-Spectrum Resistance in Rice: Exploiting

Promoteromes, Effectors and MAGIC

Alejandra I. Huerta1,2, Emily Delorean1, Ana M. Bossa-Castro1, Bradley Tonnessen1,

Alvaro L. Perez-Quintero1, Chitra Raghavan3, Rene Corral1, Valerie Verdier1,4, Hei

Leung3, and Jan E. Leach1

1 Colorado State University, Fort Collins, CO, USA 2 North Carolina State University, Raleigh, NC, USA 3 International Rice Research Institute (IRRI), Los Baños, Philippines 4 IRD, Cirad, Univ Montpellier, IPME, Montpellier, France

Disease resistance is the foundation for managing many plant diseases, because

resistant varieties have the strongest impact with minimal environmental effects or

cost. Consequently, sources of broad-spectrum resistance (BSR), or resistance that is

effective against multiple and/or diverse pathogens is of particular interest. However,

achieving BSR depends on having effective resistance sources to introduce into elite

germplasm. Multi-parent Advanced Generation Inter-Cross (MAGIC) populations are

powerful tools for identifying resistance because they have high levels of

recombination and enhanced resolution relative to biparental populations. We

screened an indica rice MAGIC population developed from eight elite founders for

BSR to diverse strains of the rice bacterial blight and leaf streak pathogens

Xanthomonas oryzae pv. oryzae (Xoo) and X. o. pv. oryzicola (Xoc), respectively. In

addition, building on our hypothesis that durable disease resistance is attainable by

targeting key microbial virulence factors, we screened for resistance to Xoo strains

isogenic for the known and common virulence factor TAL7b. A combination of

genome-wide association studies and interval mapping analyses revealed a number of

loci that conferred BSR to both Xoo and Xoc, as well as resistance targeted at

TAL7b. These BSR QTL are excellent sources for durable, broadly effective

resistance in the field.

Keywords: broad-spectrum disease resistance, quantitative trait loci, MAGIC

population


53

P03: Novel Sources of Race-Specific Resistance Gene against Bacterial

Blight of Rice in Green Super Rice Breeding Materials

Padilla JJ1, Vinarao R1,2, Sevilla MAL1, Nguyen MH1, Vera Cruz CM1, Ali J1, and

Oliva R1

1International Rice Research Institute, Los Baños, Laguna, Philippines 2Present Address: School of Agriculture and Food Sciences, University of Queensland,

St Lucia QLD 4072, Australia

Bacterial blight (BB) is one of the most economically important diseases of rice. It is

caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). A number of major

qualitative genes conferring resistance I to BB have been mapped and functionally

characterized. Although broad-spectrum R genes are more durable in the field, it is

also important to look for other sources of genes for race-specific resistance in order

to slow down the degradation of deployed qualitative R genes. In this study, putative

sources of R genes against a particular race of the pathogen are being confirmed.

About 134 Green Super Rice (GSR) inbred lines generated from multi-cross of ten

New Rice for Africa (NERICA) varieties/lines were evaluated for their resistance to

14 differential strains of Xoo, representing the ten races of the pathogen population in

the Philippines. Out of the 134, 88 lines (65.7%) show resistance to the strain PXO339

(race 9a). This resistance can only be explained by the presence of known R genes

such as Xa23, xa5 or xa25, or novel alleles of these genes. Because of their good yield

performance, 43 lines from the resistant panel were genotyped using trait –based SNP

panel in Genotyping Services Laboratory (gsl.irri.org). Genotyping confirms the

absence of major gene Xa23 in all lines while detects the presence of xa5 gene in 24

lines. Resistance to PXO339 of remaining 19 lines, those without Xa23 and xa5, is

probably due to the presence of xa25. However, three different patterns of resistance

to all strains were observed from these 19 lines: (1) resistance only to PXO339 (race

9a); (2) resistance to PXO339 and to five other strains – PXO61 (race 1), PXO112

(race 5), PXO145 (race 7), PXO280 (race 8) and PXO341 (race 10); and (3) resistance

to all isolates except to PXO71 (race 4) and PXO99 (race 6). The variation in patterns

of resistance suggests that a novel gene or allelic variants of known R genes are

responsible for the resistance of these breeding materials to race 9a.

Keywords: Green Super Rice, breeding for resistance, race-specific resistance,

bacterial blight of rice


54

P04: Over-expression of Defense-related Enzymes in Incompatible

Interactions Involving Rice Bacterial Blight Resistance Gene, Xa23 and

Five Pathotypes Xanthomonas oryzae pv. oryzae

Kamboj I, Hunjan MS, Lore JS* and Pannu PPS

Department of Plant Pathology, *Department of Plant Breeding and Genetics,

Punjab Agricultural University, Ludhiana, Punjab -141 004

Rice plant responds to attack by Xanthomonas oryzae pv. oryzae (Xoo) by activating

various defense responses. The resistance and susceptibility of crop is a character

dependent on activity of different defense related enzymes controlled by genes. Xa23

is broad-spectrum bacterial blight resistance gene identified from O. rufipogon. The

defense related enzymes including phenylalanine ammonia lyase (PAL), peroxidase

(POD), and polyphenol oxidase (PPO) are produced as a reciprocal action of infection

process by Xanthomonas oryzae pv. oryzae (Xoo) and play an important role in the

active defense mechanism of rice plant. In-planta multiplication and movement of

Xoo have a close relationship with expression of disease symptoms where lesion

length provides a measure of pathogen colonization of the rice leaf tissues. In the

current study, biochemical response of rice bacterial blight resistance gene, Xa23 was

evaluated under controlled conditions. Sixty days old plants of rice near isogenic line

IRBB23 carrying Xa23 gene and IRBB14 containing Xa14 gene (susceptible check)

grown in Conviron CMP650 plant growth chamber were clip inoculated with five

pathotypes (PbXo-4, PbXo-7, PbXo-8, PbXo-10 and Sgr-1001) of Xoo. The defense

related enzymes viz. PAL, POD and PPO were estimated from the advancing lesions

of the inoculated leaves. It was observed that all the three enzymes were over-

expressed in incompatible interactions (Xa23-PbXo-7, Xa23-PbXo-8 and Xa23-Sgr-

100). The activity of POD enzyme was found to be 19.0, 45.0, 63.9, 13.1 and 67.6

min-1g-1 fresh weight while activity of PPO enzyme was found to be 14.7, 33.9,

60.2, 11.9 and 72.3 min-1g-1 fresh weight in case of Xa23-PbXo-4, Xa23-PbXo-7,

Xa23-PbXo-8, Xa23-PbXo-10 and Xa23-Sgr-1001 interaction respectively after 96

hours of inoculation in both the cases. On the other hand, maximum activity of PAL

enzyme was observed to be 47.9, 198.2, 165.5, 37.0 and 177.1 µg t-cinnamic acid

formed h-1 g-1fresh weight in case of Xa23-PbXo-4, Xa23-PbXo-7, Xa23-PbXo-8,

Xa23-PbXo-10 and Xa23-Sgr-1001 interaction respectively after 96 hours of

inoculation. The current study showed the possible role of these three antioxidant

enzymes in imparting disease resistance in IRBB23 carrying Xa23 gene and suggests

that the disease intensity depends upon the level of expression of three defense related

enzymes in planta. The lesion length and pathogen population in the host also

correlated negatively with the level of expression of different defense related enzymes.

Keywords: Biochemical expression, X. oryzae pv. oryzae, Rice bacterial blight


55

P05: Biocontrol Assessment of Actinomycetes and Bacteria Against Rice

Bacterial Blight

Tran Ha Anh, Tran Thi Kieu, Nguyen Duc Cuong and Nguyen Thi Phong Lan

Plant Protection Department, Cuu Long Delta Rice Research Institute, Vietnam

Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is one

of the most destructive diseases of rice. The objective of this biocontrol experiments

was to identify the capable of controlling rice BB disease using actinomycetes and

bacterial strains. The results showed that, the in vitro test of antagonist Pseudomonas

fluorescens against Xoo had identified five strains (Ps.HG-11, Ps.HG-82, Ps.HG- 44,

Ps.HG-35 and Ps.HG-17) out of 158 bacteria strains expressing highly growth

inhibition. In addition, they also showed proteolytic activity. About Actinomycetes

strains, three rhizospheric isolates (AC.R.22, AC.R.44, AC.R.157) and one

endophytic isolate (AC.E.28) were the most effective isolates against Xoo. In the net

house condition, three bacterial strains (Ps.HG-11, Ps.HG-82 and Ps.HG-44) were

identified to have high control efficacy against BLB disease, among of which, Ps.HG-

11 was the most effective strain. Spraying P. fluorescens at two days before and after

pathogen inoculation showed highest control ability of BLB disease. About

Actinomycetes strains, both rhizospheric and endophytic isolates gave the good

biocontrol against BLB disease at 7 and 14 DAS of biocontrol agents, the rhizospheric

isolate (AC.R.44) was found as the highest effective biocontrol against BLB disease.

These results suggest that the further investigations should survey more efficacy

biocontrol strains of actinomycetes and bacteria againt BLB in the field condition.

Keywords: Xanthomonas oryzae pv. oryzae, biocontrol, Pseudomonas fluorescens,

Actinomycetes


56

P06: Evaluation of Rice Genetic Resource for Resistance to Xanthomonas

oryzae pv. oryzicola

Trung Nguyen Quoc, Hai Tong Van, Chau Nguyen Thi Cam, Hien Phan Thi

Faculty of Biotechnology, Vietnam National University of Agriculture

The bacterial leaf streak (BLS) in rice, caused by Xanthomonas oryzae pv. oryzicola

(Xoc), is a destructive bacterial disease, especially in autumn season. In 2018, Plant

Protection Department in Vietnam reported that 2.826 ha was infected with Xoc and

distributed mostly in northern part. This study was aimed to screen diverse germplasm

for BLS resistance in order to select potential genetic resource to identify novel

resistant gene for breeding.

We selected 113 chromosome segment substitution lines (CSSLs) from O. rufipogon

and japonica rice Asominori with genetic background of IR24 including 71 RufIL and

42 IAS lines respectively. Fifty local varieties and 5 IRBB lines carrying (Xa4, xa5,

Xa7, Xa10 and Xa21) were also tested for BLS resistance. Artificial inoculation with

2 Xoc isolate (TB4 and TN158) was carried out and measured 56horis length 10 days

after infection. CSSLs showed broad-spectrum resistance suggesting the presence of

resistance gene in O. rufipogon and Asominori variety. Highest resistance was

identified in local varieties with several accessions. Result of checking ability of XA

genes against Xoc isolates showed different reaction patterns in which xa5 had highest

resistant level.

The high resistant accessions were potential material for further gene discovery and

utilizing in breeding programs. Diverse genetic source of resistance could strengthen

Vietnamese cultivars collection against BLS in long-term.

Keywords: bacterial leaf streak, artificial inoculation, resistance, CSSLs, germplasm.


57

P07: Transcriptional Responses to Type III Secretion System Inhibitor

Ortho-Coumaric Acid of Xanthomonas oryzae pv. oryzae

Fan SS1, Tian F1, Fang LW2, Yang C-H2, He CY1



WI 53211, USA

Ortho-coumaric acid (OCA), a plant-derived phenolic compound was previously

identified as a type III secretion system (T3SS) inhibitor of the bacterial leaf blight

pathogen of rice Xanthomonas oryzae pv. oryzae (Xoo). However, the molecular

mechanisms underpinning the T3SS inhibition by OCA and the transcriptional

responses to the OCA treatments in Xoo remain to be elucidated. RNA-seq-based

transcriptomic analysis was conducted in this study to reveal changes in bacterial gene

expression in response to 30 min, 1 h, 3 h, and 6 h of OCA treatment. Results showed

that OCA significantly inhibited the T3SS gene expression, and membrane proteins in

the functional category of the cellular process appeared to be the predominant group

after 30 min of OCA treatment. More differentially expressed genes (DEGs) gathered

in the functional category of the biological process over time. Analysis of common

DEGs at all time points identified the core elements in Xoo during the response to

OCA treatment. Notably, a multidrug transporter gene cluster that encodes a MarR-

family transcriptional regulator (mdtX1), a multidrug RND transporter (mdtX2), a

multidrug transporter (mdtX3), and a MFS transporter (mdtX4) was significantly up-

regulated by OCA treatment at all time points. Genetic analysis demonstrated that

deletion of mdtX1 in Xoo affected the OCA-induced expression of mdtX2-4, but not

the OCA-inhibited T3SS expression. Therefore, our study revealed the landscape of

bacterial responses to OCA at the whole-genome transcription level, and identified an

OCA-responsive multidrug transporter cluster, which might not be specifically

involved in the T3SS inhibition in Xoo.

Keywords: Xanthomonas oryzae pv. oryzae; type III secretion system; phenolic

compound; transcription; multidrug transporter


58

P08: The EdpX1-Clpxoo Circuit Mediates Cyclic Di-GMP Signaling and

Regulates Type III Secretion System and Virulence in Xanthomonas oryzae

pv. oryzae

Xue DR1, Tian F.1, Li B., 1 Yang C-H2, He CY1



WI 53211, USA

C-di-GMP, a bacterial second messenger is synthesized by diguanylate cyclases

(DGCs, with GGDEF domains), degraded by specific phosphodiesterases (PDEs, with

EAL of HD-GYP domains) and sensed by a wide variety of c-di-GMP binding

effectors that control diverse targets, thus controlling bacterial virulence,

exopolysaccharide (EPS) production and biofilm formation. EdpX1, a confirmed PDE

was shown to regulate positively the virulence, EPS production and biofilm formation

of Xanthomonas oryzae pv. oryzae. Clpxoo, a c-di-GMP binding effector and a global

transcriptional regulator (with cNMP-/HTH DNA-binding domains) regulated similar

phenotypes mentioned above. Whether Clpxoo works with EdpX1 in same c-di-GMP

signaling pathway is further investigated in this study. ∆edpX1 not only showed

reduced induction of water soaking (WS) in rice and hypersensitive response (HR) in

tobacco, but also attenuated translocation of two T3SS effectors PXO_03702 and

PXO_04172, indicating EdpX1 regulation of T3SS functions. EdpX1 affected EPS

production and the gum gene transcription. Notably, negative regulation by EdpX1 of

transcription of clpxoo was observed. No significant change in intracellular c-di-GMP

level in wildtype and Δclpxoo existed. Remarkable reduction of c-di-GMP

concentration in ΔedpX1Δclpxoo and significant increase in ΔedpX1(clpxoo)

compared with ΔedpX1 was also found. Moreover, there was no significant difference

in c-di-GMP level in Δclpxoo and Δclpxoo(edpX1). These findings indicate that

Clpxoo significantly affects intracellular c-di-GMP levels, which might be

counteracted by EdpX1. EPS production of ΔedpX1(clpxoo) but not Δclpxoo(edpX1)

restored to the wildtype level, suggesting that Clpxoo acts downstream of EdpX1 in

regulating EPS production. Like EdpX1, Clpxoo positively regulated the induction of

WS in rice and HR in tobacco, suggesting Clpxoo regulation of T3SS functions.

Importantly, a subset of genes directly regulated by Clpxoo were identified through

chromatin immunoprecipitation sequencing (ChIP-seq), and validated by

electrophoretic mobility shift assay (EMSA) and qRT-PCR analysis, including those

encoding DGCs (GdpX5-6) and transcriptional regulators. Altogether, this study

demonstrates that Clpxoo functions in EdpX1-mediated signaling pathway in a c-di-

GMP dependent manner.

Keywords: Xanthomonas oryzae pv. oryzae, c-di-GMP signaling, receptor, T3SS,

regulation


59

P09: Role of a Host-Induced Arginase of Xanthomonas Oryzae pv. Oryzae in

Promoting Virulence on Rice

Zhang Yuqiang, Wu Guichun, Zhao Yancun, Liu Fengquan

Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences,

Nanjing 210014, China

The plant bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial

blight of rice, which is one of the most destructive diseases prevalent in Asia and parts

of Africa. Our preliminary study has discovered a host-induced protein

PXO_RS22625 in the Xoo-rice system using the proteomic method. However, little is

known about the molecular mechanism of host-induced expression of PXO_RS22625

and its regulation of virulence of Xoo. Here, we show that the deletion of the

PXO_RS22625 gene caused a significant decrease in the virulence of Xoo in the

susceptible rice cultivar IR24. Bioinformatics analysis demonstrated that

PXO_RS22625 encodes the RocF protein, which is an arginase that converts arginine

into ornithine and urea. Quantitative real-time PCR (qRT-PCR) and Western blot

assays revealed that expression of the rocF gene was significantly induced by rice and

arginine. The rocF gene deletion mutant strain showed elevated sensitivity to

hydrogen peroxide (H2O2), reduced the production of extracellular polysaccharide

(EPS) and reduced biofilm formation, all of which are important determinants for the

full virulence of Xoo, compared to those of the wild-type strain. Taken together, the

results of this study revealed a unique mechanism by which a bacterial arginase is

required for the full virulence of Xoo on rice because of its contribution to tolerance to

reactive oxygen species, production of EPS, and biofilm formation.

Key words: Xanthomonas oryzae pv. oryzae, Arginase, Virulence, Biofilm


60

P10: TalC, a Conserved Virulence Effector of African X. oryzae pv. oryzae

Strains Targeting OsSWEET14 Activates Bidirectional Transcription of a

Second Rice Locus.

Doucouré H.*1, Auguy F.*2, Blanvillain-Baufumé S.2, Fabre S.2, Thomas E.2,

Dambreville F.2, Sciallano C.2, Szurek B.2, Koita O.1, Verdier V.2, Cunnac S.2

1Laboratoire de Biologie Moléculaire Appliquée, Université des Sciences Techniques

et Technologiques de Bamako, Faculté des Sciences et Techniques (FST), Bamako,

Mali 2IRD,CIRAD, Univ Montpellier, IPME, Montpellier, France

Xanthomonas oryzae pv. oryzae (Xoo) strains that cause Bacterial Leaf Blight (BLB)

in sub-Saharan regions of Africa, limit domestic rice (Oryza sativa) production and

require breeding more resistant varieties. Type III secretion substrates of the

Transcription Activator-Like Effector (TALE) family reach the host cell nucleus

where they activate gene transcription to promote leaf colonization by binding to

specific DNA sequences termed Effector Binding Elements (EBE). Xoo major TALEs

universally target susceptibility genes of the SWEET transporter family. In nature,

polymorphism in the sequence of EBEs upstream of OsSWEET genes creates TALE-

unresponsive alleles and resistance to BLB. Similar mutations have been artificially

introduced in the OsSWEET14 susceptibility gene promoter with genome editing and

conferred resistance to some Asian Xoo strains. African Xoo strains rely primarily on

the major TALE TalC which is ubiquitous in the genomes of this group and which

also targets OsSWEET14. Recent work has established that although the virulence of a

60hor mutant strain is severely impaired, abrogating OsSWEET14 induction with

genome editing did not confer resistance to African Xoo.

To address this contradiction, we postulated the existence of a TalC target

susceptibility gene redundant with OsSWEET14. Bioinformatics analysis identified a

rice locus named ATAC (Alternative TalC target) composed of two transcripts that

were shown to be bidirectionally upregulated in a TalC-dependant but OsSWEET14

induction-independent fashion. Gain of function approaches with designer TALEs

inducing ATAC sequences did not complement the virulence of a Xoo strain incapable

of activating a SWEET gene. Furthermore, while editing the TalC EBE at the ATAC

loci compromised TalC-mediated induction, multiplex edited lines with mutations at

the OsSWEET14 and the ATAC loci remained essentially susceptible to African Xoo

strains. Collectively these results demonstrate that during Xoo infection, TalC not only

induces OsSWEET14 but also concomitantly triggers bidirectional transcription at the

ATAC locus, presumably by direct recognition of a cognate EBE. Genetic approaches

failed to unequivocally evidence a role of ATAC genes in BLB susceptibility. This

may indicate that ATAC is an off-target of TalC or that explaining its relevance in the

disease process will require disentangling the contribution of TalC and clade III

OsSWEET genes to the virulence of African Xoo strains.


61

P11: Xanthomonas oryzae pv. oryzae Employs a Host-induced Metabolic

Enzyme for Modulating its Pathogenicity

Yancun Zhao, Guichun Wu, Fengquan Liu

Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences,


Xanthomonas oryzae pv. oryzae (Xoo) that causes the bacterial blight of rice is an

important pathogenic bacterium in the world’s rice production. During Xoo-rice

interaction, a growing number of high-throughput transcriptome and proteome

analysis have discovered the induced expressions of some important virulence-related

genes. The functions of these genes are closely associated with the survival,

proliferation and synthesis of virulence factors of Xoo in rice. Here, We demonstrated

that xanA was a virulence gene whose expression could be induced in both the in vitro

Xoo-rice system and inside the rice using Western Blot, quantitative fluorescence

assay, and GUS staining. Through the prokaryotic expression and biochemical

function analysis of XanA, it was found that XanA possessed glucose phosphomutase

activity in Xoo, and regulated the dynamic balance between glucose-1-phosphate and

glucose-6-phosphate. The combined use of genomic, transcriptomic and proteomic

techniques and virulence phenotype analysis indicated that xanA regulated virulence

by influencing the utilization of carbon source by Xoo, EPS synthesis, biofilm

synthesis, flagellar motion and chemotaxis. FruA, CheY and FlhF might be the

important mediators of the above regulatory mechanism. In addition, bacterial one-

hybrid experiment and gene expression analysis revealed that carbon sources such as

xylose and galactose widely present in rice induced the expression of xanA to varying

degrees. The gene xanA itself received regulation by the AraC family transcriptional

regulators such as PXO_06036. Taken together, the AraC family transcriptional

regulators may play important roles in virulence regulation by xanA and host-induced

expression of xanA in rice.

Keywords: Xanthomonas oryzae pv. oryzae, Pathogenicity, xanA, Virulence factor


62

P12: Engineering Broad-Spectrum Bacterial Blight Resistance by

Disrupting Variable TALE-Binding Elements of Multiple Susceptible

Genes in Rice

Xu Zhengyin1, Wang Sai1, Yang Yangyang1, Liu Longyu1, Li Ziyang1, Li Ying1, Ma

Wenxiu1, Zhu Bo1,2, Zou Lifang1,2 and Chen Gongyou1,2

1School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of

Urban Agriculture by Ministry of Agriculture of China, Shanghai 200240, China; 2State Key Laboratory of Microbial Metabolism, School of Life Sciences &

Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China

Xanthomonas oryzae pv. oryzae (Xoo), causal agent of bacterial blight of rice, recruits

transcription activator-like effectors (TALEs) to induce expression of OsSWEET

genes, which function in sugar transport and disease susceptibility. To engineer broad-

spectrum bacterial blight resistance, we used CRISPR/Cas9-mediated gene editing to

disrupt the TALE-binding elements (EBEs) of two S genes, OsSWEET11 and

OsSWEET14, in rice cv. Kitaake, which harbors recessive resistance allele

Xa25/OsSWEET13. The engineered rice line MS14K exhibited broad-spectrum

resistance to most Xoo strains with a few exceptions, suggesting that the compatible

strains may contain new TALEs. We identified Tal5LN18 and Tal7PXO61, PthXo2-like

TALE effectors, as major virulence factors in the compatible Xoo strains LN18 and

PXO61, respectively, and found that Xoo encodes at least five types of PthXo2-like

effectors. Given that PthXo2/PthXo2.1 target OsSWEET13 for transcriptional

activation, the genomes of 3000 rice varieties were analyzed for EBE variations in

OsSWEET13 promoters, and ten Xa25-like haplotypes were identified. Tal5LN18 and

Tal7PXO61, were shown to bind slightly different EBE sequences in the OsSWEET13

promoter and activated its expression. CRISPR/Cas9 technology was then used to

generate InDels in the EBE of the OsSWEET13 promoter in the mutant MS14K. This

resulted in the creation of new germplasm with three edited OsSWEET EBEs and

broad-spectrum resistance against all Xoo strains tested. Our findings illustrate how to

disarm TALE-S co-evolved loci to generate broad-spectrum resistance through the

loss of effector-triggered susceptibility.

Key words: Xanthomonas oryzae pv. oryzae, TALE, susceptible gene, ETS, RLS


63

P13: Role of an Orphan Response Regulator in Promoting Virulence of

Xanthomonas oryzae pv. oryzae on Rice

Pandey A

Microbial Technology Division, CSIR-Central Institute of Medicinal and Aromatic

Plants, Lucknow- 226015, India

Two component systems (TCSs) are one of the most prevalent ways by which bacteria

sense, respond, and adapt to various changes in their environment. We are using Rice-

Xanthomonas oryzae pv. oryzae (Xoo; the causal agent of rice disease called bacterial

blight) pathosystem to understand the role of TCSs in plant-microbe interaction.

Genome sequence analysis revealed that Xoo strains are equipped with large

repertoire of TCSs. TCS constitute a signal transduction mechanism which is basically

formed by two proteins: a membrane bound histidine kinase sensor and a cytoplasmic

response regulator. Sensor histidine kinase responds to an environmental change or

stimulus by phosphorylating a cognate response regulator which triggers changes in

cellular physiology or gene expression in order to enhance adaptability. A system

level mutagenesis in an Indian Xoo strain BXO1 led to identification of several

virulence genes encoding for response regulators. Here, work will be presented

indicating importance for an orphan response regulator (encoded by BXO1_05645

gene) for Xoo virulence on rice. This response regulator contains the CheY-like

receiver domain and is required for in planta growth as well as migration, suppression

of host defense response, induction of non-host resistance, optimum expression of

type 3 secretion system, EPS production, motility, biofilm formation and survival

under specific stress conditions.


64

P14: Biosynthesis of Coenzyme Q in the Phytopathogen Xanthomonas via a

Yeast-Like Pathway

Zhou Lian, Wang Xing-Yu, He Ya-Wen




Coenzyme Q (CoQ) is a lipid-soluble, membrane component found in organisms ranging

from bacteria to mammals. The biosynthesis of CoQ has been intensively studied in E. coli

where twelve genes, ubiABCDEFGHIJKX, are involved. The phytopathogens Xanthomonas

campestris pv. campestris (Xcc) and X. oryzae pv. oryzae (Xoo) produce CoQ8 as the major

ubiquinone. Interestingly, both Xcc and Xoo contain no homologues of the E. coli

64horismite lyase-encoding ubiC. They instead contain the gene xanB2 (Xcc4014 in Xcc

and PXO_3739 in Xoo, respectively) which encodes a novel bifunctional chorismatase

needed for the biosynthesis of both 4-HBA and 3-HBA. The XanB2-dependent 4-HBA is

required for CoQ8 biosynthesis. The other genes involved in Xcc CoQ8 biosynthetic

pathway remain to be elucidated. In this study, we first investigated the putative genes for

CoQ8 biosynthesis in the phytopathogen Xcc using a combination of bioinformatics, genetic

and biochemical methods. We showed that Xc_0489 (coq7Xc) encodes a di-iron carboxylate

monooxygenase filling the E. coli UbiF role for hydroxylation at C-6 of the aromatic ring.

Xc_0233 (ubiJXc) encodes a novel protein with an E. coli UbiJ-like domain organization and

is required for CoQ8 biosynthesis. The Xcc decarboxylase gene remains unidentified.

Further functional analysis showed that ubiB and ubiK homologues ubiBXc and ubiKXc are

required for CoQ8 biosynthesis in Xcc. Deletion of ubiJXc, ubiBXc and ubiKXc led to the

accumulation of an intermediate, 3-octaprenyl-4-hydroxybenzoic acid (OHB). UbiKXc

interacts with UbiJXc and UbiBXc to form a regulatory complex. Deletion analyses of these

CoQ8 biosynthetic genes indicated that they are important for virulence in Chinese radish.

These results suggest that the Xcc CoQ8 biosynthetic reactions and regulatory mechanisms

are divergent from those of E. coli. The variations provide an opportunity for the design of

highly specific inhibitors for the prevention of infection by the phytopathogen Xcc.

Keywords: Xanthomonas, Coenzyme Q, biosynthetic pathway.


65

P15: Biosynthesis of the Yellow Pigments Xanthomonadin Involves an ATP-

dependent 3-HBA: ACP Ligase and an Unusual Type II Polyketide Synthesis

Pathway

Cao Xue-Qiang, Zhou Lian, He Ya-Wen




The genus Xanthomonas represents one of the most ubiquitous groups of plant-associated

bacterial pathogens. A characteristic feature of the genus Xanthomonas is the production of

yellow, membrane-bound pigments called xanthomonadins. Xanthomonadins play an

important role in maintaining the ecological fitness of Xanthomonas species by protecting

bacterial cells against photooxidative and peroxidative stress. A pig cluster is responsible for

xanthomonadin biosynthesis. Previously, Xcc4014 of the cluster was characterized as a

bifunctional chorismatase that produces 3-hydroxybenzoic acid and 4-HBA in X. campestris

pv. campestris (Xcc)(Zhou et al., Molecular Microbiology. 2013: 87: 80-93). This study

further characterized the roles of several other genes within the pig cluster. (1) Deletion

analysis identified a total of eleven genes to be essential for xanthomonadin biosynthesis.

Biochemical and bioinformatics analysis suggests that xanthomonadins are synthesized via

an unusual type II-polyketide synthesis pathway. Heterologous expression of the pig cluster

in Pseudomonas aeruginosa resulted in the synthesis of chlorinated xanthomonadin-like

pigments. These results further confirmed the role of pig cluster in xanthomonadin

biosynthesis. (2) We demonstrated that xanC encodes an acyl carrier protein (ACP) while

xanA2 encodes a bifunctional ATP-dependent 3-HBA:ACP ligase. Both of them act together

to catalyze the formation of 3-HBA-S-ACP from 3-HBA to initiate xanthomonadin

biosynthesis. (3) Finally, we showed that xanH encodes a FabG-like enzyme and xanK

encodes a novel glycosyltransferase. Both xanH and xanK are not only required for

xanthomonadin biosynthesis, but also required for the balanced biosynthesis of extracellular

polysaccharides and DSF-family quorum sensing signals. Accordingly, we propose a

schematic model that describes xanthomonadin biosynthetic pathway. These findings

provide us with a better understanding of xanthomonadin biosynthetic mechanisms and

directly demonstrate the presence of extensive cross-talk among xanthomonadin

biosynthetic pathways and other metabolic pathways.

Keywords: Xanthomonas, yellow pigments, type II polyketide synthesis pathway.


66

P16: Application of Genome Editing Technology for Improving the

Bacterial Leaf Blight Disease Resistance of Vietnamese Important Rice

Cultivars Bacthom 7 and TBR225

Cao Le Quyen1, Vu Hoai Sam2, Nguyen Thanh Ha1, Phung Thi Thu Huong1, Pham

Thu Hang1, Nguyen Van Cuu1, Nguyen Thi Thu Ha1, Pham Thi Van1, Vu Mai Ha1,

Nguyen Duy Phuong1, Sebastien Cunnac3, Pham Xuan Hoi1

1Agricultural Genetics Institute, Hanoi, Vietnam 2National Institute of Medicinal Materials, Hanoi, Vietnam 3UMR Interactions Plantes Microorganismes Environment (IPME), IRD-CIRAD-

Universite, Montpellier, France,

Xanthomonas oryzae pv. oryzae (Xoo) causes serious bacterial leaf blight (BLB)

disease to many Vietnamese important rice cultivars, including Bacthom 7 and

TBR225. Recently, marker-assisted selection (MAS) has been successfully used to

developed BLB resistant rice cultivars in Vietnam. However, the practical use of

MAS in rice breeding programs is limited for various reasons, including genetic

background interactions of identified quantitative trait loci (QTL), large genotype-by-

environment interaction effects. In this project, genome editing technology is firstly

used to improve the BLB resistance of popular rice variety Bacthom 7 and TBR225.

The high-efficient Bacthom 7 and TBR225 gene transformation protocols were

developed for editing target genes involved in the infection of Vietnamese Xoo strains

in these varieties. Nearly 300 Xoo isolates were collected from 22 provinces within

recent 6 years in Vietnam and identified the virulence on Bacthom 7 and TBR225

varieties. Several isolates were demonstrated that they were virulent on Kitakee wide-

type line but not on SWEET14 mutant line. Additionally, the expression of SWEET14

and SWEET11 in Bacthom 7 rice plants were induced by the infection of some of

these isolates in RT-PCR experiments showed the particular involvement of

SWEET14 and SWEET11 genes to BLB disease in Bacthom 7. On the first stage of the

project, some Bacthom 7 T0 transgenic lines containing a mutation at well-known Tal5

and/or TalC EBE(s) on the promoter region of SWEET14 gene were successfully

generated and grown in greenhouse. On next stages, phenotype and genotype of T1

and T2 SWEET14-edited lines will be investigated to confirm the role of SWEET14

gene in Xoo infection in Bacthom 7 rice variety. The transcription activator-like

(TAL) effector genes of some representative Xoo strains will be sequenced to

identified other target effector binding elements (EBEs) on the promoter of

susceptible genes for editing by CRISPR/CAS9. The main goal of the project is to

generate improved Bacthom 7 and TBR225 varieties with a broad-spectrum resistance

against Vietnam Xoo strains.

Keywords: Bacthom 7, genome editing, SWEET11, SWEET14, TBR225


67

P17: Ascent of CRISPR-Cas in the Macrocosm of Genome Engineering:

Application in Photophilic Rice

Prasanta K Dash*, Soumydeep Mukherjee, Nagendra K Singh

ICAR- National Institute of Plant Biotechnology, PUSA campus, New Delhi, India

Manipulation of genome in post-genomic era has been revolutionized by advent of

CRISPR-Cas. Amongst the genome manipulation methodologies such as ZFN,

meganucleases and TALEN that fall short of reproducible statistical significance have

been replaced by cost effective, precise and reproducible CRISPR technology.

CRISPR is the RNA integrant of a ribonucleo-protein complex that guides Cas, the

proteinaceous molecular scissor to cleave target site proximal to the conserved PAM

sequence in the genome while CRISPR-RNA engenders editing. Alleviation of

deleterious effects of biotic and abiotic stresses in plants and animals is an important

use of targeted genome editing by CRISPR. Cardinally important crop such as rice

exposed to harsh biotic and abiotic stress produce sub-optimal quality and quantity of

yield. Amongst many, pathogenic leaf blight, is a major challenge to ideal growth and

yield of rice. Nonetheless, diverse applications in plants including multiplex gene

mutation, gene replacement, and transcriptional control makes CRISPR a superior

alternative to conventional breeding methods. Loss-of-function of susceptible genes

by CRISPR mediated knockouts have earlier been utilized to generate plants tolerant

to herbicide, and endemic bacterial blight. Here, we scale the remarkable success of

CRISPR technology, its canonical role and promises it offers to offset the biotic

stresses and restoration of parity/ productivity in economically important photophilic

staple food rice.


68

ICBB06 List of Participants

CHINA

Dr. Bo Zhu

School of Agriculture and Biology

Shanghai Jiao Tong University

800 Dongchuan RD. Minhang District

Shanghai, China

Email: [email protected]

Dr. Chao Yu

Institute of Plant Protection, Chinese

Academy of Agricultural Sciences, Beijing

100193, China


Dr. Fengquan Liu

Institute of Plant Protection, Jiangsu

Academy of Agricultural Sciences,



Dr. Fenghuan Yang



100193, China


Dr. He Ya-Wen

School of Life Sciences and Biotechnology

Shanghai Jiao Tong University


Shanghai, China


Dr. Huamin Chen



100193, China


Dr. Lifang Zou




Shanghai, China


Dr. Zhengyin Xu




Shanghai, China


Dr. Yancun Zhao

Institute of Plant Protection, Jiangsu

Academy of Agricultural Sciences,



FRANCE

Dr. Mathilde Hutin

UMR IPME, IRD-CIRAD-Université

Montpellier, Montpellier, France


Dr. Sebastian Cunnac

IRD, CIRAD, Université Montpellier, IPME,

Montpellier, France


mailto:[email protected]


69

Dr. Valerie VERDIER

Institut de Recherche pour le Développement

911 av Agropolis, Montpellier, 34000, France


GERMANY

Dr. Sarah Schmidt

Heinrich Heine University

Düsseldorf, Germany


Dr. Wolf Frommer

Heinrich Heine University, Düsseldorf,

Germany


INDIA

Dr. Deo Mishra

Bayer BioScience, Plot No. 13, Software

Layout, Madhapur, Hyderabad-500081


Dr. Kalyan Mondal

Division of Plant Pathology, ICAR-Indian

Agricultural Research Institute, New Delhi

110012


Dr. Jagjeet Singh Lore

Department of Plant Pathology, Department

of Plant Breeding and Genetics, Punjab

Agricultural University, Ludhiana, Punjab -

141 004


Dr. Gurjit Singh Mangat

Department of Plant Breeding and Genetics

Punjab Agricultural University, Ludhiana-

141004, Punjab, India


Dr. Reeny Mary Zacharia

Rice Research Station, Moncompu,

Alappuzha, Kerala

[email protected]

Dr. Sachin Khedekar

Advanta India Limited

Hyderabad, Telangana


INDONESIA

Dr. Hardian Susilo Addy

Department of Plant Protection. Faculty of

Agriculture, University of Jember


Ms. Rejeki Desi

Graduate School of Biotechnology,

University of Jember


INTERNATIONAL RICE RESEARCH INSTITUTE (IRRI)

Dr. Ricardo Oliva

International Rice Research Institute, Los

Banos, Laguna 4031 Philippines


Dr. Christian Paolo Balahadia





70

Dr. Jonas Padilla




Dr. Marian Hanna Nguyen




JAPAN

KOREA

Dr. Seiji Tsuge

Kyoto Prefectural University, Kyoto, Japan


Dr. Lin-Woo Kang

Department of Biological Sciences, Konkuk

University, 120 Neungdong-ro, Gwangjin-gu,

Seoul 05029


MALAYSIA

SENEGAL

Mrs. Kogeethavani Ramachandran

Rice and Paddy Research Centre, Malaysian

Agriculture and Development Institute,

Selangor 43400


Dr. Hamidou Tall

Institut Sénégalais de Recherches Agricoles

(ISRA), Bel Air, Dakar Sénégal


MALI

Dr. Hinda Doucoure

Laboratoire de Biologie Moléculaire

Appliquée, Université des Sciences

Techniques et Technologiques de Bamako,

Faculté des Sciences et Techniques (FST),

Bamako


THE UNITED STATES

Dr. Jan E. Leach

Colorado State University, Fort Collins,

CO, USA


Dr. Jonathan M. Jacobs

Department of Plant Pathology and Infectious

Disease Institute, Ohio State University,

Columbus, OH, USA


Dr. Adam J. Bogdanove

Plant Pathology and Plant Microbe

Biology Section, School of Integrative

Plant Science, Cornell University, Ithaca,

NY USA Email: [email protected]

Dr. Alvaro L Perez-Quintero

Colorado State University, Fort Collins,

CO, USA Email: [email protected]


71

Dr. Jillian Lang

Department of Bioagricultural Sciences

and Pest Management, Colorado State

University, Fort Collins, CO, USA

[email protected]

VIETNAM

Dr. Le Quoc Doanh

Vice Minister

Ministry of Agriculture and Rural

Development (MARD)

2 Ngoc Ha, Ba Dinh, Ha Noi, Vietnam

Dr. Nguyen Hong Son

President

Vietnam Academy of Agricultural Sciences

(VAAS), Thanh Tri, Ha Noi, Vietnam


Dr. Nguyen Quang Tin

Department of Sciences, Technology and

Environment, MARD

No. 2 Ngoc Ha, Ba Dinh, Ha Noi,

Vietnam

Mr. Bui Quang Dang

Vietnam Academy of Agricultural Sciences

Thanh Tri, Ha Noi, Vietnam


Mr. Nguyen Kim Chien


Environment, MARD

No. 2 Ngoc Ha, Ba Dinh, Ha Noi, Vietnam

Dr. Bui Ba Bong

Former Vice Minister

Ministry of Agriculture and Rural

Development

No. 2 Ngoc Ha, Ba Dinh, Ha Noi, Vietnam

Mr. Nguyen Truong Giang


Environment, MARD


Vietnam

Dr Pham Van Du

VNSAT Project Adviser, MARD


Vietnam

Mr. Le Thanh Tung

Department of Crop Production

MARD, Vietnam

Mr. Tran Van Dung

National Agricultural Extension Center

No 16, Thuy Khue, Tay Ho, Ha Noi,

Vietnam

Mr. Le Van Thiet

Department of Plant Protection

MARD, Vietnam

Mr. Le Quoc Cuong

Southern Regional Plant Protection

Center, Department of Plant Protection,

MARD, Vietnam

Mr. Mai Van Hao

Nha Ho Research Institute for Cotton and

Agriculture Development


Dr. Tran Tuan Tu

Ministry of Sciences and Technology

No. 113 Tran Duy Hung, Ha Noi, Vietnam


72

Dr. Tong Van Hai




Dr. Nguyen Huy Chung

Plant Protection Research Institute,

Vietnam


Dr. Nguyen Quoc Trung




Dr. Pham Thien Thanh

Field Crops Research Institute, Vietnam


Dr. Nguyen Thi Thu Nga



Dr. Vo Thi Minh Tuyen

Agricultural Genetics Research Institute,

Vietnam


Dr. Tran Vu Phen



Dr. Cao Le Quyen

Agricultural Genetics

Research Institute, Vietnam


Dr. Le Thanh Toan



Dr. Nguyen Thi Minh Nguyet

Agricultural Genetics Research Institute,

Vietnam

Mr. Nguyen Van Huan

Bayer Vietnam Ltd.


Mr. Bui Van Kip

Bayer Vietnam Ltd.


Mr. Nguyen Tran Anh Huan

Bayer Vietnam Ltd.


Mr. Nguyen Hoang Son

Bayer Vietnam Ltd.


Mr. Dang Van Phuoc

Bayer Vietnam Ltd.


Dr. Tran Ngoc Thach


Institute, Tan Thanh village, Thoi Lai

district, Can Tho city, Vietnam

Dr. Nguyen Thuy Kieu Tien




Dr. Huynh Van Nghiep




Dr. Duong Hoang Son




Dr. Hoang Dinh Dinh


Dr. Tran Ngoc Tu



73





Dr. Tran Dinh Gioi




Dr. Ho Le Thi




Dr. Vu Tien Khang




Dr. Nguyen Thi Phong Lan




Dr. Doan Manh Tuong




Dr. Trinh Quang Khuong




Dr. Nguyen Duc Cuong




Dr. Nguyen The Cuong




Dr. Vo Thi Bich Chi




Dr. Do Duc Tuyen




Dr. Dang Minh Tam




Dr. Tran Thi Thanh Xa




Dr. Tran Vu Hai




Dr. Nguyen Thanh Linh




Dr. Bui Thanh Liem




Dr. La Cao Thang




Dr. Nguyen Cao Quan Binh



Dr. Le Quang Long




74

district, Can Tho city, Vietnam district, Can Tho city, Vietnam

Dr Nguyen Huu Minh




Dr. Vu Quynh




Ms Tran Thi Anh Thu




Dr. Pham Thi Be Tu




Ms. Nguyen Le Van




Ms. Tran Thi Thuy




Mr. Nguyen Ngoc Hoang




Ms. Tran Nhu Ngoc




Ms. Dang Thi Tho




Ms Mai Nguyet Lan




Ms. Nguyen Thi Duong




Ms. Nguyen Kim Thu




Ms. Duong Vy Thao




Mr. Nguyen Duc Thanh




Mr. Nguyen Khoa Nam




Mr. Nguyen Van Hieu




Ms Vo Thi Thu Ngan




Mr. Nguyen Khac Thang





75

Ms Vo Thi Da Thao




Ms. Nguyen Thi Xuan Mai




Mr. Tran Phuoc Loc




Ms. Tran Thi Kieu




Ms. Tran Thi Nam Ly




Ms. Tran Ha Anh




Ms. Tran Thi Mong Quyen




Ms. Nguyen Thi Thanh Thuy




Mr. Do Tan Trung




Ms. Nguyen Thi Kim Vang




Ms. Nguyen Kim Vang




Ms. Tran Thi Be Hong





76

General Information

Conference venue

The 6th International conference on Bacterial Blight of Rice will be held at Muong

Thanh Luxury Can Tho, a five-star hotel in Can Tho city, Vietnam. The conference

hall “Tran Giang A Ballroom” is equipped with state-of-the-art LED screen visual and

audio facilities. The screen size is 400 cm x 900 cm, 16:9 viewing ratio.

Official language

The official language of the conference is English.

Visas

Visitors from certain countries with valid passports and tickets for their onward

journey do not require visas for a period time, depending on country. Please check this

website for information on visa exemption to Vietnam, https://lanhsuvietnam.gov.vn.

However, entry visas are required for restricted nationals, stateless persons, and those

from countries that have no diplomatic relations with the Philippines. Please contact

Vietnam Embassy/ Consulate nearest you to check the countries on the visa required

Climate

The climate is generally hot and humid. The time of the Conference coincides with the

season of rains and thunderstorms. It is advised that participants bring appropriate

clothing. In August, average weather temperature in Can Tho city, is 25-32°C/77-89°F.

Currency

Foreign currency may be exchanged to local currency (Vietnamese Dong) at the

airport and most major hotels. The exchange rate is relatively the same at the airport

and all major banking facilities in Can Tho. The Vietnam Dong is the currency used in

the whole country. The exchange rate as of August 2019: 23,200 to 23,250

Vietnamese dongs.

Electricity

In Vietnam, 220 volts is used, alternating at 60 cycles per second. Flat prongs plugs

are acceptable. Adapters can be obtained locally but it is better to bring your own.

Internet access

Internet access at Muong Thanh Can Tho Hotel is free. All other hotels have Internet

access.

ATMs and credit cards

ATMs are available in Muong Thanh Can Tho Hotel and in some public areas. All

major establishments accept American Express, Mastercard, and Visa. Expect a 3-5%

surcharge. In general, banks are open from Monday to Friday, 9:00 a.m.-3:00 p.m.

https://lanhsuvietnam.gov.vn/


77

Insurance

We recommend that all participants obtain personal travel and life insurance for their

trip.

Safety and Security Precautions

Although Can Tho City is friendly to visitors, travelers are advised to take the

necessary precautions. Do not walk alone in unpopulated streets after dark or before

dawn. Take a taxi to go to a restaurant or an entertainment place that is far from your

hotel, especially in the evenings. Try to walk-in a group and do not draw unnecessary

attention to yourself by wearing meeting badges, carrying large sums of money, or

wearing jewelry. Lock your cash and valuables in your hotel safe when you do not

need them.

Health Regulations

A certificate of vaccination against yellow fever is required for travelers coming from

infected areas. Otherwise, visitors are not required to take any vaccination.

Registration

The registration desk will open on 18 August 2019 (Sunday) from 2:00 to 7:00 p.m

and on 19 August from 7:30 to 8:30

Conference bags

Delegates, speakers, and other special guests will be given conference bags at the

registration area. Each bag contains the program, the abstract book, ID and some

materials from sponsors.

Dress code

Participants are advised to be in business attire during the conference. Casual clothing

may be worn during field visits.

Exhibition area

Exhibits will be displayed at the foyer and in the corridors near the conference hall

(Tran Giang A Ballroom). It will be open from 8:00a.m.to 5:00p.m.

Food and refreshments

Morning and afternoon snacks will be served at the Tran Giang A Ballroom. Buffet

Lunch will be set-up at the second floor of the hotel.

Green policy

We promote the green policy through the judicious use of available resources and

recycling of materials. Help us recycle plastics, glass, cans, and papers. Before you

leave the venue, please put your IDs and unused materials in drop boxes in designated

areas or surrender the items at the registration counter.

Mobile devices

It is highly recommended that mobile phones be put in silent mode throughout the

duration of the conference to avoid disrupting the proceedings.


78

No smoking policy

Smoking in the conference area is strictly prohibited.

Speakers’ presentation

Speakers should submit their final presentation, saved in a USB flash drive, to the AV

technician at the speakers’ desk. All presentations should be in PowerPoint format.

For details please refer to “Guidelines for Speakers”.

Welcome Reception and Social Program

All participants are invited to attend the Gala Dinner which will be hosted by the

Local Organizer in the Cam Thi Giang Banquet Hall, the 3nd Floor of the Muong

Thanh Can Tho Hotel, on 19 August, from 6:00 to 8:00 p.m. Participants may take

this opportunity to catch-up with friends and build networks with colleagues from

different institutions, universities and the industry while learning from various

scientists/researchers through the Welcome reception. While having dinner, guests

will be entertained with national and traditional music plays and songs to have a feel

of the Vietnamese culture.

Speakers’ Information

All speakers are requested to follow the instructions below:

1. Please submit your PowerPoint presentation to the speakers’ desk located at the

left wing of the Tran Giang A Ballroom during registration. In case video films

are combined with the PowerPoint, please make sure to make a test-run in the

designated session hall at least 30 minutes before the start of the session (even

though you have already checked it in the Speakers’ Desk).

2. If you are willing to share your presentation with participants, please display your

email address on the last slide of the presentation.

3. Kindly be ready at least 15 minutes before your session to meet your session

chairperson and fellow speakers.

Please follow the instructions of the chairperson in charge.

Each invited speaker is given 20 minutes to present their lecture; an additional 5

minutes will be allocated for discussion after the presentation.

Important note for Macintosh users

To use Mac presentations on a PC-compatible computer, note that you need to prepare

it according to the instructions below before bringing it to the speakers’ desk:

- Use a common font, such as Arial, Times New Roman, Verdana, etc. Special fonts

might be changed to a default font on a PowerPoint-based PC.

- Insert pictures as JPG files (and not TIF, PNG, or PICT- these images will not be

visible on a PowerPoint-based PC).

- Use a common movie format, such as AVI, MPG, or WMV (MOV files from

QuickTime will not be visible on a PowerPoint-based PC). Instructions to Poster

Presenters:


79

Poster presentations will be done at the Tran Giang A Ballroom foyer (see map).

The poster should fit the poster board- ~100 cm (width) x ~120 cm (height).

The poster must be shown in the properly designated board (consult the Secretariat for

board assignment).

Stand beside your poster for the whole duration of the presentation proper and

encourage your audience to engage in a discussion about your presentation. Follow

the instructions given by the chairperson.

Set up your poster on 18 August 1:00 at 5:00 p.m, or during registration time (before

8:30) of 19 August.

Dismantle your poster display on 20 August after 6:00 p.m.


80

Venue Maps

The 4th Floor Plan of the Muong Thanh-Can Tho Hotel

The Conference Venue: Tran Giang A Ballroom


81

The Ground Floor Plan of the Muong Thanh-Can Tho Hotel

Documents

The 6th International Conference on Bacterial Blight …icbb6.org/wp-content/uploads/2019/08/Abstract_Book.pdfThe 6th International Conference on Bacterial Blight of Rice 1 Sponsors