Regional heritability mapping reveals genomic regions and candidate defense genes for multi-race anthracnose resistance in Phaseolus vulgaris

Anthracnose, caused by Colletotrichum lindemuthianum, is one of the most damaging diseases affecting common bean (Phaseolus vulgaris). This study applied regional heritability mapping (RHM) to an Andean diversity panel of 225 accession phenotyped against seven races of the pathogen (7, 39, 55, 65, 73, 2047 and 3481). Moderate-to-high genomic heritability (32–59%) and an LD decay of 13.97 kb supported the resolution of RHM. Twelve significant genomic regions associated with multi-race resistance were detected across chromosomes Pv01, Pv02, Pv04, Pv08 and Pv11. Regions on Pv01, and Pv02 showed positional correspondence with previously reported Co-1 and Co-u loci, while four contiguous regions on Pv04 contained clusters of leucine-rich repeat (LRR) genes and protein kinases associated with pathogen recognition and signaling. Additional regions on Pv08 and Pv11 were associated with resistance to race 3481 and included genes encoding calcium-binding and ubiquitin-associated proteins. Functional annotation of 202 predicted proteins revealed enrichment of phosphorylation, ubiquitination, ion binding, and plasma membrane–related processes, supporting multilayered defense mechanisms. These findings corroborate previously reported loci, reveal novel genomic regions, and highlight functionally coherent candidate genes. To our knowledge, this is the first application of RHM to dissect disease resistance in common bean, providing useful targets for further validation and marker development in anthracnose-resistance breeding programs.