|VIDIGAL FILHO, PEDRO - Universidade Estadual De Maringá|
|GONCALVES-VIDIGAL, MARIA - Universidade Estadual De Maringá|
|SOUSA, VANET - Universidade Estadual De Maringá|
|BISNETA, MARIANA - Universidade Estadual De Maringá|
|Pastor Corrales, Marcial - Talo|
|OBLESSUC, PAULA - University Of California, Davis|
|MELOTTO, MAELI - University Of California, Davis|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2020
Publication Date: 8/18/2020
Citation: Vidigal Filho, P.S., Goncalves-Vidigal, M.C., Sousa, V.B., Bisneta, M.V., Pastor Corrales, M.A., Oblessuc, P.R., Melotto, M. 2020. Genome-wide association study of resistance to the anthracnose and angular leaf spot diseases in Brazilian Mesoamerican and Andean common bean cultivars. Crop Science. https://doi.org/10.1002/csc2.20308.
Interpretive Summary: Anthracnose and angular leaf spot are destructive diseases of common bean in the world, particularly in dry bean producing countries of the Americas, but also in countries of Eastern and Southern Africa. Both diseases are caused by pathogens that recurrently produce new virulent strains. Because genetic resistance is the most cost-effective strategy to control these pathogens, finding new sources of resistance is a major priority of breeding projects. New resistance genes enable breeders to develop new common bean cultivars with effective resistance. To that end, 57 Andean and 58 Middle American traditional common bean varieties from five Brazilian states were evaluated for their reactions to five and to two different virulent strains of the anthracnose and angular leaf spot pathogens, respectively. Some common bean varieties from the Andean gene pool were resistant to all virulent strains of both pathogens. In addition, a DNA genome assay was used to find resistance traits to both pathogens in the Middle American and Andean traditional varieties. A special type of resistance trait, named quantitative resistance locus, was found in common beans from both gene pools. The quantitative resistance trait was attributed to DNA regions on multiple chromosomes of the common bean. These results may used by bean breeders in the government, at universities, or at private institutions to transfer these defined anthracnose and angular leaf spot resistance traits to newly developed commercial common bean cultivars.
Technical Abstract: Anthracnose (ANT) and angular leaf spot (ALS) are devastating diseases of common bean in the world, then the identification of new sources of ANT and ALS resistance is a major priority in breeding programs. The ANT and ALS reaction of 57 Andean (A) and 58 Middle American (MA) cultivars from five Brazilian states were evaluated. Three MA and eight A cultivars were resistant to 9, 31 65, 73, 2047 and 3481 races, and four MA and 14 A were resistant to four of the ANT pathogen races. Furthermore, thirteen MA and 30 Andean cultivars were resistant to races 31-23 and 63-39 of the ALS pathogen. To understand the genetic basis of ANT and ALS resistance the genome-wide association study (GWAS) was conducted using 115 cultivars. This study revealed new sources of resistance to both diseases in A and MA. The quantitative resistance loci (QRL) associated with races 9 and 73 of ANT pathogen was positioned on chromosome Pv04; resistance to race 65 on Pv01, Pv04 and Pv08; resistance to races 2047 and 3481 on Pv10, and Pv05, respectively. Furthermore, QRL associated with race 31-23 of P. griseola were mapped on chromosomes Pv02 and Pv06, whereas to race 63-39 was mapped to Pv03, Pv06 and Pv08. Previously developed markers are only effective in two-parent mapping populations; however, the high-density markers obtained through GWAS specifically tag ALS and ANT resistance loci throughout the bean genome, these results could guide bean breeding programs aiming to transfer of ANT and ALS resistance to commercial cultivars.