Identification of candidate genes for resistance to ascochyta blight in pea by combining transcriptomics and high-throughput mapping of differentially expressed genes

Abstract

Peyronellaea pinodes (Syn. Didymella pinodes), causing ascochyta blight, is the most destructive foliar pathogen of dry peas. Resistance to this disease is quantitative and polygenic. Quantitative Trait Loci (QTLs) associated with resistance have been identified, but the genes underlying these QTLs are unknown. The objective of this study is to identify candidate genes for resistance to ascochyta blight in pea by selecting genes differentially expressed in resistant reactions and located into QTLs associated with resistance. With this aim, in the frame of “LEGATO” project, a detailed transcriptomic study was carried out, using MACE technique, to identify genes differentially expressed in the resistant accession P665 compared to the susceptible one cv. Messire. The resulting MACE sequences were used to identify SNPs between P665 and cv. Messire for these differentially expressed genes. These SNPs were further genotyped in the RIL populatio n P665 x Messire in a high-throughput way by sequencing MACE libraries from 94 RIL families. The mapping of these differentially expressed genes in the P665 x Messire genetic map and the study of their possible co-localization with the QTLs associated with resistance to P. pinodes is in progress.