Mapping Ur-6, a Bean Rust Resistance Gene in Common Bean

Abstract

Bean rust, caused by the fungus Uromyces appendiculatus (Pers.:Pers) Unger, is a disease of common bean (Phaseolus vulgaris) prevalent in the Americas and Africa. The most cost-effective countermeasure to bean rust is genetic resistance. While 17 dominant rust resistance genes (named with Ur- symbol) have been identified in common bean, not all of these genes have been genetically fine-mapped. To expand our knowledge of rust resistance genes in common bean, Ur-6 was mapped in the common bean genome. A GWAS analyses suggested that Ur-6 is present on chromosome Pv07 of P. vulgaris. Two InDel markers tightly linked to Ur-6 were developed by F2 bi-parental mapping and may prove effective for marker-assisted selection in bean breeding programs in the future. Further, 25 candidate genes were identified and are the potential focus of future gene validation research.