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