|COSTA, LARISSA - Universidade Federal De Lavras
|NALIN, RAFAEL - University Of São Paulo
|DIAS, MARIANA - Universidade Federal De Lavras
|FERREIRA, MARCIO - Embprapa
|Pastor Corrales, Marcial - Talo
|SOUZA, ELAINE - Universidade Federal De Lavras
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2020
Publication Date: 11/1/2020
Citation: Costa, L.C., Nalin, R.S., Dias, M.A., Ferreira, M.E., Song, Q., Pastor Corrales, M.A., Hurtado-Gonzales, O.P., Souza, E.A. 2020. Different loci control resistance to different isolates of the same race of Colletotrichum lindemuthianum in common bean. Theoretical and Applied Genetics. 134:543-556. https://doi.org/10.1007/s00122-020-03713-x.
Interpretive Summary: Anthracnose is one of the most important diseases of common bean. Although many sources of resistance to anthracnose have been identified, anthracnose remains one of the major factors limiting production in tropical areas of Latin America and Eastern Africa where environmental conditions favor disease development. Race 65 of anthracnose is currently problematic and the development of cultivars resistant to race 65 is a major goal. Little progress, however, has been made due to the quick loss of resistance caused by pathogen mutations. In this study, USDA and Brazilian researchers identified genes in beans that control resistance to different isolates of anthracnose. They also identified 25 common bean cultivars resistant to all five major isolates of race 65 by analyzing a diverse panel of common beans. This study provides breeders in industry, at government agencies, and at universities new genetic resources to improve resistance to anthracnose in common beans and novel DNA markers of genes that can help accelerate breeding for disease resistance.
Technical Abstract: Development of varieties with durable resistance to anthracnose is a major challenge in common bean breeding program because of the extensive variability of Colletotrichum lindemuthianum pathogen. In order to tap genomic regions associated with resistance to different isolates of Race 65, we developed a MesoAmerican F2 population from BRS Estilo x Ouro Vermelho cross and inoculated the population with two different isolates of Race 65, we also selected a diverse common bean panel containing 189 MesoAmerican accessions and inoculated with five different isolates of Race 65. The recombinant inbred lines and accessions were genotyped with BARCBean6K_3 Illumina BeadChip containing 5,398 SNP markers. Both linkage and genome-wide association analyses identified different loci controlling resistance to different isolates of race 65 on linkage group Pv04. Genome-wide association analysis also detected loci on Pv05, Pv10 and Pv11 that were resistant to Race 65 isolates. These findings indicate that resistance to anthracnose Race 65 can be overcome by pathogenic variability among isolates of the same race and could lead to the quick loss of resistance after cultivar release. Evaluation of the diverse panel also identified 25 common bean cultivars resistant to all five Race 65 isolates. The accessions and new loci resistance to different isolates of Race 65 are anticipated to facilitate pyramiding of resistance genes and provide durable resistance to anthracnose in common bean.