Alternaria spp. Associated with Potato

Foliar Diseases in China 引起马铃薯叶部病害的链格孢菌种类鉴定

Prof. Xuehong Wu (E-mail: wuxuehong@cau.edu.cn)

Department of Plant Pathology, China Agricultural University

吴学宏 教授/博士生导师

（手机：13601272810；电子邮件：wuxuehong@cau.edu.cn）

中国农业大学植物病理学系

Main Contents (主要内容)

1. Introduction (研究背景)

2. Technical Route (研究内容)

3. Results (研究结果)

4. Conclusions and Discussions (结论和讨论)

Potato ranks as the fourth most important staple food crop after

rice, wheat, and maize.

马铃薯是仅次于水稻、小麦、玉米之后的第四大粮食作物。

In China, culture areas of potato is about 5 million hectares (25%

of the world) . 我国种植面积500万公顷（25%）。

1.1 Importance of Potato Crop

1.1 马铃薯的重要性

World potato production (Metric tones by count) China :74,799,084

China has the largest growing

area and consumption of potato

in the world.

1.2 Potato Foliar Diseases

1.2 马铃薯叶部病害

1) Potato early blight (In 1892, USA), caused by

Alternaria solani

1892年美国首先报道茄病链格孢菌引起马铃薯早疫病。

2) Potato brown spot (In 1984, Israel), caused by A.

alternata

1984年以色列报道交链格孢菌引起马铃薯褐斑病。

3) Potato leaf spot (In 2010, Iran)， caused by A.

alternata, A.tenuissima, A. dumosa, A. solani, A.

arborescens,A. infectoria and A. longipes.

2010年伊朗报道交链格孢菌等7种引起马铃薯叶斑病。

Early blight (1892, USA),

Brown spot (1984, Israel),

Leaf spot (2010, Iran）

早疫病（1892，美国） 褐斑病（1984，以色列） 叶斑病（2010，伊朗）

1.3 Alternaria spp. associated with potato foliar diseases

1.3引起马铃薯叶部病害的链格孢菌种类

Alternaria solani,

A. alternata,

A. interrupta,

A. grandis,

A. tenuissima,

A. dumosa,

A. arborescens,

A. infectoria.

Alternaria solani,

A. alternata

Worldwide China

(Hebei, Heilongjiang)

We want to know

An accurate understanding of the pathogen

composition is crucial for efficient disease

management.

引起病害的病原菌种类的准确鉴定才能进行有效地防治。

Whether the other six species already existed or will

appear later in the potato growing areas of China ?

How about their spatial distribution？

另外六种国际上已报道的链格孢菌在中国是否存在，它们的分布情况如何？

2. Technical route

2. 研究内容

Sampling of diseased potato leaves with symptoms

采集发病的病害叶片

Alternaria fungi isolation, purification, and preserve

链格孢菌的分离、纯化和保存

Alternaria species identification (morphology, molecular biology)

采用形态学和分子生物学方法进行种类鉴定

Pathogenicity on potato (spore suspension inoculation)

致病性试验（采用孢子悬浮液的方法）

黑龙江

吉林

内蒙古 新疆

宁夏 山西

河北

甘肃

山东

浙江

福建

云南

四川

贵州

湖南 江西

安徽

河南

湖北

海南

西藏

青海

台湾

陕西

辽宁

重庆

江苏

广西 广东

A total of 511 Alternaria isolates were obtained from 193 locations

in 16 provinces, autonomous regions, and municipalities of China.

中国16个省市自治区采样分离得到511株链格孢菌

c

d b

a

f

e

Fig.1 Leaf sample collection (a, b) ; Pathogen isolation (c, d)

and purification (e, f)

Fig. 2 Colony and microscopic morphologies of Alternaria species a-c：Colonies of A. tenuissima，A. alternata，A.

solani ；d-f：Conidia of A. tenuissima，A. alternata，A. solani ；g-h：Sporulation pattern of A. tenuissima and A. alternata

2.1 Morphological traits observation

Species Colony Sporulation

Conidiophore Conidia

Septum Shape Size/ µm Shape Size/ µm

A.t

loosely

cottony,

greyish-

green to

olive

brown

unbranched

conidial

chains with

one or two

lateral

branches

occasionally

short,

arising

singly

16.0-71.2

× 2.6-

6.2

typically

ovoid to

obclavate

22.5-3.4×

8.2-14.2

transverse

septa:1-6

longitudinal

septa:0-2

A.a

densely

turfy

dark gray

to black

brown,

with

numerous

secondary and

occasionally

tertiary chains

single or

fasciculat

e, straight

or bent

22.5-79.6

× 2.0-

4.9

obpyriform

to ellipsoid

20.8-0.5×

7.6-12.0

transversal

septa: 3-8

longitudinal

septa: 0-3

A.s

dense dark

gray to

black

Not observed

simple conidiophores

bearing dark,

multiseptate conidia

with one or

two beak

102.0-15.0

×15.0-

25.0

transverse

septa: 9-11

longitudinal

septa: 1-2

Table 1 Morphological traits of Alternaria species

2.2 Molecular identification

A. solani A. tenuissima / A. alternata

Phylogenetic tree constructed based on the sequences of the ITS regions

of rDNA of 55 A. tenuissima, 23 A. alternata, 9 A. solani isolates, as well

as 15 reference sequences retrieved from GenBank.

A. solani A. alternata A. tenuissima

Phylogenetic tree constructed based on the partial coding sequences of histone 3 gene

of 55 A. tenuissima isolates, 23 A. alternata isolates, 9 A. solani isolates, as well as 9

reference sequences retrieved from GenBank

Geographic origins Numbers

of locations

Numbers of Alternaria isolates

A. tenuissima A. alternata A. solani

Inner Mongolia Autonomous Region (I M) 32 119 (27) 13 (10) 3 (3)

Hebei province (HB) 52 41 (19) 10 (2) 16 (16)

Beijing Municipality (BJ) 1 3 (1) 1 (1) 0

Shandong Province (SD) 30 56 (15) 18 (10) 0

Shanxi Province (SX) 1 1 (1) 0 0

Shaanxi Province (SAX) 1 3 (1) 1 (1) 0

Ningxia Hui Autonomous Region (NX) 28 66 (18) 3 (3) 8 (8)

Gansu Province (GS) 22 25 (5) 21 (4) 3 (3)

Heilongjiang Province (HLJ) 10 30 (9) 5 (4) 0

Jilin Province (JL) 2 3 (2) 0 0

Liaoning Province (LN) 1 3 (1) 0 0

Chongqing Municipality (CQ) 4 10 (4) 7 (2) 0

Yunnan Province (YN) 3 8 (3) 6 (2) 0

Guizhou Province (GZ) 3 6 (2) 2 (1) 0

Sichuan Province (SC) 1 4 (1) 0 0

Xinjiang Uygur Autonomous Region (XJ) 2 8 (1) 8 (2) 0

Total 193 386 (110) 95 (42) 30 (30)

Ratio - 75.5% 18.6% 5.9%

Table 2 Alternaria isolates obtained from the diseased leaf samples

Alternaria

链格孢菌

Disease incidence

发病率 (%)

Disease index

病情指数

A. tenuissima 10.0-48.0 (30.9±6.7) 30.83-55.33 (44.98±5.53)

A. alternata 10.0-55.7 (34.3±4.8) 30.83-58.33 (46.61±6.26)

A. solani 41.1-45.6 (44.2±1.9) 55.83-58.11 (57.75±1.31)

A. tenuissima

细极链格孢

A. alternata

交链格孢 A. solani

茄病链格孢

4.1 A. tenuissima was the most prevalent (75.5%), and widely

distributed in all the sixteen provinces, autonomous regions, and

municipalities, followed by A. alternata (18.6%), and A. solani

(5.9%). This is the first report of A. tenuissima causing potato

foliar diseases in China. 细极链格孢菌为优势种群，其次为交链格孢和茄病链格孢。这是国内首次系统研究报道。

4.2 The other five Alternaria species including A. dumosa, A.

arborescens, A. infectoria, A. grandis, and A. interrupta reported to

cause potato foliar diseases in other countries, were not detected in

the present study. 国际上已报道的另外5种链格孢菌未见报道。

4. Conclusions and discussions

4.结论和讨论

4.3 The ITS sequences of rDNA were able to differentiate A.

solani isolates from small-spored Alternaria isolates; histone 3

gene were successfully used in differentiating the small-spored

Alternaria isolates that were hard to classify by morphological traits

or ITS sequence. ITS区可以用于区分大孢子链格孢与小孢子链格

孢菌，组蛋白基因还可以区分不同的小孢子链格孢菌。

4.4 Since A. tenuissina is predominant in the isolates obtained, we

therefore propose that A. tenuissima should be treated as the

major target in decision of management strategies. 细极链格孢

菌应作为生产中防治的重点对象。

Publications related to Alternaria

Causing potato diseases

1) Wu X. H (Corresponding Author). 2013. First Report of

Alternaria Blight of Potato Caused by Alternaria tenuissima in

China, Plant Disease. 97(9): 1246.

2) Wu X. H (Corresponding Author). 2015. Characterization of

Alternaria species associated with potato foliar diseases in China,

Plant Pathology, 2015,64(2):425-43

1）Wu X H (corresponding author). Characterization of a new anastomosis

group (AG-W) of binucleate Rhizoctonia, causal agent for potato stem canker. Plant

Disease, 2015,99(12):1757-1763.

2）Wu X H (corresponding author). Anastomosis group and pathogenicity of

Rhizoctonia solani associated with stem canker and black scurf of potato in China.

European Journal of Plant Pathology, 2015,143(1):99-111.

3）Wu X H (corresponding author). Potato stem canker caused by binucleate

Rhizoctonia AG-G in China. Journal of General Plant Pathology, 2015,81(4):287-

290

4）Wu X H (corresponding author). Anastomosis groups and pathogenicity of

binucleate Rhizoctonia isolates associated with stem canker of potato in China.

European Journal of Plant Pathology, 2014, 139(3): 535-544.

Publications related to Rhizoctonia

causing potato diseases

Thanks for your attention! Prof. Xuehong Wu

E-mail: wuxuehong@cau.edu.cn

Department of Plant Pathology, China

Agricultural University, Beijing 100193