Resistance to Clover yellow vein virus in Common Bean Germplasm

Clover yellow vein virus (ClYVV) is a potentially devastating viral pathogen of temperate common bean (Phaseolus vulgaris L.) production. Recent research demonstrated that resistance to ClYVV is conditioned by bc-3 and bc-32 and that a nonsynonymous mutation in P. vulgaris eukaryotic translation initiation factor 4E (PveIF4E) is the putative functional determinant of this resistance. The objective of this research was to expand the characterization of ClYVV resistance in common bean through greenhouse-based phenotypic evaluation of 391 accessions of the USDA P. vulgaris Core Collection, a collection of 99 snap bean cultivars and breeding lines, and an extended host differential panel of 75 genotypes with known response to other viral pathogens and to determine if previously designed Kompetitive Allele Specific Polymerase Chain Reaction (KASP) assays could be validated for future bc-3 resistance allele mining. As a result, one accession from the Core Collection, one additional snap bean breeding line, and 19 dry bean genotypes representing most major market classes of common bean were identified to be resistant. All genotypes that remained symptomless throughout the evaluation were demonstrated to possess mutations in PveIF4E that corresponded with either bc-3 or bc-3(2). In addition, the bc-u bc-2(2) allele combination and the By-2 allele were also demonstrated to condition resistance phenotypes to ClYVV. These results synthesize a new model for genetic resistance to ClYVV and validate the use of the KASP assays for large-scale bc-3 allele mining.