Sequence tagged site markers linked to the sbm1 gene for resistance to pea seedborne mosaic virus in pea

Resistance to pea seed-borne mosaic virus (PSbMV) pathotype P-1 in peas is conferred by sbm1 with recessive inheritance. PSbMV is an economically important pathogen with world-wide distribution that causes significant losses in pea yield and reduces seed and produce quality. The sbm1 gene was previously mapped to linkage group VI on molecular linkage maps of the pea genome. To improve plant breeders' ability to develop varieties resistant to PSbMV, two random amplified polymorphic DNA markers (G05_2537 and L01_910) and one restriction fragment length polymorphism (P446) linked to sbm1 have been identified. The genomic sequences for these markers have been characterized and the information used to develop three simple polymerase chain reaction-based STS (sequence tagged site) assays. Linkage analysis in two F-2 populations showed that the most tightly linked of these three STS loci (sG05_2537) is approximately 4 cM from sbm1 . Characterization of a collection of resistant and susceptible germplasm demonstrated a strong correlation between STS alleles and sbm1 alleles, indicating the utility of these markers for marker-assisted selection in breeding programmes using a range of germplasm sources.