Molecular Characterization of Anthracnose Resistance Gene Co-12 in the Navy Bean Variety Bolt

Anthracnose of common bean (Phaseolus vulgaris L.), caused by the fungus Colletotricum lindemuthianum, is a destructive seed-borne disease of dry beans. We genotyped a navy bean recombinant inbred line population with genome-wide SNP markers and phenotyped the population in the field disease nurseries and in the growth cabinets under inoculation with race 73 of C. lindemuthianum. A 3.2 cM region on Pv01, corresponding to a 300 kbp region on the physical map at the previously-identified Co-1 locus, was found associated with anthracnose resistance in different disease evaluations, accounting for up to 85% of the variation. In silico search of the region in the P. vulgaris reference genome identified 4 candidate genes at the putative Co-1 locus and all four candidate genes were polymorphic between resistant and susceptible parents. The gene Phvul.001G243500, on chromosome 1, is currently the strongest candidate gene for an anthracnose R-gene at the Co-1 locus in Bolt.