Development of Novel Markers Associated with Pea Enation Mosaic Virus Resistance on LG III of Pea Based on Comparative Mapping

Pea enation mosaic virus (PEMV) is an important disease of cool season food legumes. The present investigation was carried out to study the inheritance and identify molecular markers linked with the PEMV resistance gene (En) in field pea (Pisum sativum L.) using an F₇-derived mapping population developed from the cross, ‘Lifter’ (resistant)/‘Radley’ (susceptible). Three hundred ninety-four pea recombinant inbred lines (RILs) were phenotyped for PEMV reaction and showed a 1:1 resistant:susceptible segregation ratio in the field and greenhouse screenings. We developed EST-based markers through an Intron Targeted Amplified Polymorphism (ITAP) approach based on comparative mapping with Medicago truncatula and a targeted region amplified polymorphism (TRAP) approach from the genomic region segregating for En. Our results confirm that resistance to PEMV in pea is governed by a single dominant gene, En located on the linkage group III between markers CNGC (2.5 cM) and tRNAMet2 (1.3 cM) with many other closely associated markers. The combination of these two markers predicts the presence of En with 99.4% accuracy. They have implications for marker assisted selection for PEMV resistance in pea improvement breeding programs.