Tagging and Mapping Pse-1 Gene for Resistance to Halo Blight in Common Bean Differential Cultivar UI-3

Halo blight [caused by Pseudomonas syringae pv. phaseolicola (Burkh.) Young et al. (Psp)] is a serious seed-borne bacterial disease of common bean (Phaseolus vulgaris L.). A few resistance (R) genes and quantitative trait loci provide control to one or more races of the pathogen. To better understand monogenic resistance and improve breeding efficiency, we sought to tag and map a gene (Pse-1) in host differential cultivar UI-3 (previously named 'Red Mexican UI-3') that provides resistance to races 1, 5, 7, and 9 of Psp. Cosegregation for resistance to races 1, 5, 7, and 9, in a recombinant inbred population, 'Canadian Wonder'/UI-3 (CU), confirmed the effect of Pse-1 against multiple races of the pathogen. Bulked-segregant analysis in the CU population identified six random amplified polymorphic DNA (RAPD) markers tightly linked (0-3.3 cM) to Pse-1. Three of the RAPDs completely linked with Pse-1 in the CU population were converted to sequence characterized amplified region (SCAR) markers SH11.800, SR13.1150, and ST8.1350. The linked markers were used to integrate Pse-1 to linkage group B10 of the core map. Allelism tests (F2) confirmed relationships of Pse-1 and Pse-4 derived from UI-3 with R genes in the other host differential cultivars. A survey of advanced lines and cultivars revealed that the SCAR markers generated in this study will have utility for marker-assisted selection of Pse-1 in germplasm from the Andean gene pool (e.g., kidney, calima) and from race Mesoamerican within the Middle American gene pool (black, carioca).