Host plant resistance against insect pests

in pepper and tomato

Ben Vosman

Asian Solanaceous Round Table 2017

Why insect resistance research

� Direct damage

● Through feeding

● Honeydew, molds

� Indirect damage

● Virus transmission

� Yield and quality loss

� Problems increase

● Ban on insecticides

● Climate change

host plant resistance

How do plants defend themselves

Direct defense

physical and/or chemical traits

Indirect defense

Volatiles

predators

parasitoids Growth rate

Reproduction

Mortality

Focus of our research: Sap feeding insects

� Phloem feeders

● Whiteflies

● Aphids

� Cell content feeder

● Thrips

Aims of our research

� Identification of new sources of resistance

● Germplasm screens

� Characterization of the resistance

● Bioassays (population development, choice – no-choice experiments, behavior studies), Metabolomics

� Molecular markers + genes

● Segregating populations

● Genomics, candidate genes

� Resistance mechanism

Germplasm screens

� Solanaceae

● Aphid resistance in potato and pepper

● Thrips resistance in pepper

● Whitefly resistance in tomato and pepper

� Brassica

● Thrips, cabbage aphid, rootfly and whiteflyresistance in cabbage

� Others

● Thrips resistance in onion and leek

● Aphids in lettuce and lily

Several good sources identified

Resistance often present in CWR

Characterization of the resistance

� Thrips resistance in pepper

● Identification of sources

● Effect on different life stages of thrips

● QTL mapping of thrips resistance and metabolites

� Insect resistance in tomato

● Identification of sources

● QTL mapping

● Chemical characterization

Screening of pepper for thrips resistance

screenhouse glasshouse

cuttingleafLeaf disc

Good sources identified

Survival rate of immature states on pepper

Maharijaya, et al. (2012) EEA 145:62%71

QTL mapping

� F2 population, 196 individuals

● R female: C. annuum AC 1979

● S male: C. chinense 4661

� Phenotyped for thrips resistance and metabolites

QTL for thrips resistance

P14M48-3230.0

E32M49-40619.8

E32M49-52048.9E35M58-44653.6E35M58-28061.1HmpsE11371.2Hpms1_577.7Epms_37679.9

HpmsE078108.1

HpmsAT2-20123.7P17M32-227129.1

P11M48-159148.4

HpmsE088168.0

HpmsE014181.0

E35M49-332197.4

damage

surv.L2

surv.pupa0 5

10

15

20

25

30

P06

42% – 51%

explained variance

Maharijaya, et al. 2015 TAG 128:1945–1956

Metabolites correlated with larval survival

P14M48-3230.0

E32M49-40619.8

E32M49-52048.9E35M58-44653.6E35M58-28061.1HmpsE11371.2Hpms1_577.7Epms_37679.9

HpmsE078108.1

HpmsAT2-20123.7P17M32-227129.1

P11M48-159148.4

HpmsE088168.0

HpmsE014181.0

E35M49-332197.4

damage

LC2703

LC6636

surv.L2LC

3072

LC2514

surv.pupaO

ctacosane

Capsianoside-III

GC

1607

LC5046

GC

2054

GC

19100 5

10

15

20

25

P06

Capsianoside and unknown compound LC5046:corr with resistance;Co-localization but no known effects on insects

Maharijaya, et al. unpublished

Conclusions on thrips resistance

� Good resistance sources identified

� Resistance blocks larval development

� Based on one major QTL

� Some metabolites correlate and co-locate with resistance

● Unclear if they are causal

Insect resistance in tomato

� Screening Lycopersicon group of Solanum sectionLycopersicon for insect resistance

● S. lycopersicum

● S. pimpinellifolium

● S. cheesmaniae

● S. galapagense

� Characterization of resistance

● QTL mapping

● metabolomics

Pest insects used:

● Whitefly: Trialeurodes vaporariorum

● Aphid: Myzus persicae

● Caterpillar: Spodoptera exigua

● Thrips: Frankliniella occidentalis

Resistance parameters and correlations

whitefly survival wh

i te

f ly s

urv

i va

l

wh

i te

f ly o

vip

os i

tio

n

thr i

ps

surv

i val d

ay

2

thr i

ps

surv

i val d

ay

3

thr i

ps

surv

i val d

ay

4

cat e

r pilla

r su

r viv

al

cat e

r pilla

r w

eig

ht

ap

hid

su

r viv

al

whitefly oviposition 0.89

thrips survival day 2 0.62 0.57

thrips survival day 3 0.70 0.55 0.63

thrips survival day 4 0.60 0.39 0.41 0.78

caterpillar survival 0.51 0.36 0.24 0.46 0.65

caterpillar weight 0.38 0.43 0.32 0.29 0.30 0.82

aphid survival 0.74 0.77 0.38 0.64 0.57 0.44 0.40

aphid nymphs 0.41 0.60 -0.03 0.29 0.26 -0.02 0.02 0.68

S. pimpinellifolium (5 acc.)

S. cheesmaniae (3 acc.)

S. galapagense (3 acc.)

Reference materials (4 acc.)

Overview survival data

S. habrochaites

S. cheesmaniae

S. galapagense

cv. Moneymaker

S. pimpinellifolium

S. pennellii

Whitefly Thrips Caterpillar Aphid

LA716 a LA716 a PV110096 a PV110083 a

PV110114 ab PV110114 ab PV110118 a PV110114 a

LA1777 bc PV110083 abc LA1777 a LA716 a

PI134418 c PV110059 abcd PV110083 a LA1777 a

PV110083 d PI134418 abcd PV110114 a PI134418 a

PV91102 de LA1777 abcd PI134418 a PV91102 a

PV110118 de PV110118 bcd PV110112 a PV110118 a

PV110059 ef PV110096 bcd PV110086 a PV110059 b

cv. MM ef PV110112 bcd LA716 a PV110057 bc

PV110061 ef PV110086 bcd PV110057 b PV110096 bc

PV110112 ef PV110061 cd cv. MM bc cv. MM bcd

PV110096 ef PV110057 cde PV91102 b PV110061 cd

PV110057 ef PV91102 de PV970017 d PV110112 de

PV110086 f cv. MM e PV110059 cd PV970017 e

PV970017 f PV970017 e PV110061 d PV110086 e

Trichomes

All accessions resistant against whitefly, aphids and thrips had trichomes type IV.

� No correlation was found between PS and the presenceof trichome type I or IV, suggesting a different mechanism at this level

I

IV

VI

Metabolomics on the accessions

� Comparing metabolites among the lycopersicon group accessions

� 2 bulks of each 3 plants

� LCMS analysis

● Untargeted

● Analysis focused on acyl sugars

� 2565 metabolites detected among 11 accessions

PCA analysis of the accessions

Based on all metabolites

S. cheesmaniaeS. galapagenseS. pimpinellifoliumcv. Moneymaker.

Acyl sugars are partly species specific

Heatmap shows the 229 acyl sugars detected

LA716

LA716

LA1777

LA1777

PI134418

PI134418

MM

PV110057

PV110057

MM

PV110096

PV110086

PV110061

PV110061

PV110086

PV110096

PV110112

PV970017

PV110112

PV110114

PV110114

PV110083

PV110083

PV110118

PV110118

PV110059

PV110059

PV091102

PV091102

F2 population created

� Several sources for good whitefly resistance available in S. galapagense and S. pimpinellifolium.

� Further analysis using F2 populations

● S. galapagense and S. lycopersicum

● Phenotyped in the Netherlands and Indonesia for B. tabaci resistance

● Genotyped using a SNP array

QTL Mapping

� Large effect QTL found on chromosome 2 for Adult survival, Oviposition rate and trichome type, all at thesame position

� Additional minor QTLs for Adult survival and Oviposition rate on chromosome 9

� 54% of AS explained

0

5

10

15

20

0 20 40 60 80 100 120 140 160

LOD ScoreChromosome 2

Firdaus et al 2013 TAG 126:1487-1501

Acyl sugars in 10 R and 10 S plants of F2

Conclusions on insect resistance in tomato

� The S. galapagense accessions are resistant against several insects.

� S. pimpinellifolium accessions differ in resistance. Some show resistance, others are susceptible.

� S. cheesmaniae accessions are generally susceptible towards insects.

� There is a huge variation in metabolites among the accessions, some correlated to resistance

� Analysis of an F2 population showed a major QTL for whitefly survival on chromosome 2

General Conclusions

� Good resistance sources identified in several crops

● Resistance often present in (old) landraces and Crop Wild Relatives

● More emphasis on conservation of CWR needed

� Resistance mechanisms still largely unclear

● Different mechanisms in different crops

● Trichomes – no trichomes

� Good perspectives for resistance breeding

Acknowledgements:

WUR Plant Breeding

� Roeland Voorrips

� Olga Scholten

� Sjaak van Heusden

� Koen Pelgrom

� Greet Steenhuis-Broers

� Betty Henken

� Martijn van Kaauwen

� Wendy van ‘t Westende

Former PhD students

� Colette Broekgaarden

� Awang Maharijaya

� Syarifin Firdaus

� Alejandro Lucatti

WUR Entomology

� Joop van Loon

WUR Bioscience

� Ric de Vos

Sponsors:

Questions?

Firdaus, 2012

Contact: ben.vosman@wur.nl