Kolade O.A., J. Orjuela, G. Maillot, S. Chéron,

M.N. Ndjiondjop, A. Ghesquière and L. Albar

Towards the identification of genetic factors that control resistance of Oryza glaberrima to Rice yellow mottle virus

Rice yellow mottle virus

First described in 1970Endemic to AfricaInsect / mechanical transmissionDamages on high yielding varieties

Introduction

SusceptibilityO. sativa indicaO. glaberrima

Partial resistanceO. sativa japonica

High resistanceO. sativa indicaO. glaberrima

Introduction contd.

High resistance

O. sativa : 2 accessions, 1 resistance source

Gigante

Bekarosaka

O. glaberrima : at least 29 accessions and 5

independent resistance sources

Tog5681

Tog5674

Tog5672

Tog7291

Tog5307

RYMV1 (allele -2)

RYMV1 (alleles -3, -4, -5)

RYMV2

SusceptibilityO. sativa indicaO. glaberrima

Partial resistanceO. sativa japonica

High resistanceO. sativa indicaO. glaberrima

Introduction contd.

High resistance

O. sativa : 2 accessions, 1 resistance source

Gigante

Bekarosaka

O. glaberrima : at least 29 accessions and 5

independent resistance sources

Tog5681

Tog5674

Tog5672

Tog7291

Tog5307

RYMV1 (allele -2)

RYMV1 (alleles -3, -4, -5)

RYMV2

RYMV1 encodes eIF(iso)4Gresistance conferred by point mutations

MAS on rymv1-2

SusceptibilityO. sativa indicaO. glaberrima

Partial resistanceO. sativa japonica

High resistanceO. sativa indicaO. glaberrima

Introduction contd.

High resistance

O. sativa : 2 accessions, 1 resistance source

Gigante

Bekarosaka

O. glaberrima : at least 29 accessions and 5

independent resistance sources

Tog5681

Tog5674

Tog5672

Tog7291

Tog5307

RYMV1 (allele -2)

RYMV1 (alleles -3, -4, -5)

RYMV2

RYMV2 probably encodes CPR5-1resistance allele = null allele

RYMV2-CPR5-1 alone is not sufficient to confer resistance in IR64

A better characterization of RYMV2 mediated resistance Diversity on RYMV2 candidate gene research of locus interacting with RYMV2 to confer

resistance

Genetic basis of Tog5307 resistance

Objectives

Diversity on RYMV2 candidate gene

Analysis of CAPS/CPR5-1 on a

collection of rice accessions

Diversity on RYMV2 candidate gene

IR64 To

g729

1

IR64

Tog7

291

Htz

agarose

QIAXCEL analyser

O. sativa (56 Acc.)

O. barthii (107 Acc.)

O. glabberima (241 Acc.)

No

of a

cces

sion

sDiversity on RYMV2 candidate gene

Alleles

Tog7291 and 6 resistant accessions

Test of statistical associations between candidate loci and resistance BC1-F3 [(Tog7291 x IR64) x Tog7291] population 14 F3 families fixed for CPR5-1 (RR) and in segregation for resistance QTLs or candidate gene regions

Research of additional loci involved in Tog7291 resistance

Putative impact of the region containing CPR5-2 gene on Tog7291 resistance

Tog7291 allele

IR64 allele

Htz

Genetic basis of Tog5307 resistance

Tog7291 x Tog5307

F2

F3 families in segregation for Tog7291 and Tog5307

resistance

Selection of F2 without Tog7291 resistance

F3(R) x F3(S)

Pseudo-F2 & pseudo-F3 families

F2: 62R/20S (p>0.05 for 1 dom. gene)F3: 265R/141S (p>0.05 for 1 dom.gene)

F3:191R/153S (p>0.05 for 1 dom.gene)

Tog5307’s resistance dominant

Conclusions

• CAPs marker CPR5-1 showed higher diversity in African species

• CPR5-1 and CPR5-2 maybe interacting to confer resistance

• Tog5307’s resistance is dominant and oligogenic• Pyramiding of these genes : a very promising

solution for durable RYMV resistance

Acknowledgements

• ALL IRD DIADE TEAM: DR ALBAR AND DR ALAIN GHESQUIERE

• ALL AFRICA RICE BIOTECHNOLOGY TEAM :DR NDJIONDJOP