The soil-borne pathogenPhytophthora capsicicauses severe destruction ofCapsicumspp. Resistance inCapsicumagainstP. capsiciis controlled by numerous minor quantitative trait loci (QTLs) and a consistent major QTL on chromosome 5. Molecular markers onCapsicumchromosome 5 have been developed to identify the predominant genetic contributor to resistance but have achieved little success. In this study, previously reported molecular markers were used to reanalyze the major QTL region on chromosome 5 (6.2 Mbp to 139.2 Mbp). Candidate resistance gene analogs (RGAs) were identified in the extended major QTL region including 14 nucleotide binding site leucine-rich repeats, 3 receptor-like kinases, and 1 receptor-like protein. Sequence comparison of the candidate RGAs was performed between twoCapsicumgermplasms that are resistant and susceptible, respectively, toP. capsici.11 novel RGA-based markers were developed through high-resolution melting analysis which were closely linked to the major QTL forP. capsiciresistance. Among the markers, CaNB-5480 showed the highest cosegregation rate at 86.9% and can be applied to genotyping of the germplasms that were not amenable by previous markers. With combination of three markers such as CaNB-5480, CaRP-5130 and CaNB-5330 increased genotyping accuracy for 61Capsicumaccessions. These could be useful to facilitate high-throughput germplasm screening and further characterize resistance genes againstP. capsiciin pepper.
Development of Clustered Resistance Gene Analogs-Based Markers of Resistance toPhytophthora capsiciin Chili Pepper
