Characterization of genetic resistance in Andean common bean cultivar Amendoim Cavalo to Colletotrichum lindemuthianum

Abstract

The Anthracnose, caused by Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara, is one of the most importante fungal disease of common bean. Several strategies have been used for its control, such as the use of pathogen-free seeds, chemical control and crop rotation. However, the most efficient method to control this disease is the use of resistant cultivars. Previous studies conducted by the Laboratory of Common Bean Breeding and Molecular Biology of the Nucleus of Research Applied to Agriculture (Laboratório de Melhoramento de Feijão Comum e de Biologia Molecular do Núcleo de Pesquisa Aplicada à Agricultura-NUPAGRI) revealed that the Andean cultivar Amendoim Cavalo is resistant to races 2, 7, 9, 19, 23, 39, 55, 65, 73, 89, 1545, 2047 and 3481 of C. lindemuthianum. The objective of this work was to characterize the genetic resistance to anthracnose in Amendoim Cavalo using inheritance and allelism tests. The results of inheritance tests in F2 generation of Amendoim Cavalo × PI 207262 cross, inoculated with 2047 race, fitted in a ratio of 3R:1S, proving the action of a single dominant gene in Amendoim Cavalo cultivar. Allelism tests demonstrated that the dominant gene present in Amendoim Cavalo is independent from the genes previously characterized. The authors propose the Co-AC symbol to designate the new resistant gene to C. lindemuthianum. The results show high contribution to breeding programs, once Amendoim Cavalo cultivar can be considered an important Andean source of resistance to C. lindemuthianum.

Fine mapping of an anthracnose-resistance locus in Andean common bean cultivar Amendoim Cavalo

“…Thus, this study showed that AC was resistant to races that were widespread in many countries, suggesting that AC had broad resistance to the anthracnose pathogen. The inheritance of resistance tests conducted by Nanami et al [42] and during this study indicated that the resistance of AC was conferred by a single dominant gene. Therefore, the objectives of this study were to fine-mapping the anthracnose-resistance locus in AC and to develop DNA markers tightly linked to this locus.…”

“…Segregating F 2 populations from the cross between the resistant AC and the susceptible differential cultivars PI 207262 and G 2333, when inoculated with race 3481, revealed an anthracnose-resistance locus in AC, provisionally called Co-AC, which segregated as a monogenic dominant locus. Nanami and collaborators previously reported that anthracnose resistance in AC was conditioned by a single dominant gene [42]. These authors performed several allelism tests including crosses between AC and the cultivars Michigan Dark Red Kidney (Co-1), Jalo Vermelho (Co-12), Jalo Listras Pretas (Co-13), Pitanga (Co-14), and Paloma (Co-Pa), which have anthracnose-resistance loci located on Pv01, and concluded that based on these allelism tests, the anthracnose resistance of AC was independent of the anthracnose-resistance genes found in the other five cultivars used in the tests.…”

“…The initial anthracnose-resistance study showed that AC was resistant to the Andean race 2 and the Mesoamerican races 65, 73, and 2047 of C. lindemuthianum [42]. Races 2, 65 and 73 of C. lindemuthianum have been reported to occur in multiple states of Brazil, as well as in numerous countries of the Americas, Africa, and other continents [12][13][14][15].…”

Integration of anthracnose resistance loci and RLK and NBS‐LRR‐encoding genes in the Phaseolus vulgaris L. genome

“…‘Amendoim Cavalo’ stands out due to its broad‐spectrum resistance to common bean ANT. Co‐AC confers resistance to Races 2, 7, 9, 19, 23, 39, 55, 65, 73, 89, 1545, 2047, and 3481 (Nanami et al., 2017). This gene was fine‐mapped in the 9‐kb region between the SNP markers SS102 and SS165 using race 3481.…”

New Andean source of resistance to anthracnose and angular leaf spot: Fine-mapping of disease-resistance genes in California Dark Red Kidney common bean cultivar

“…The results of studies of the allelic relationship between the anthracnose resistance gene in the Andean common bean cultivar CDRK crossed with MDRK and Amendoim Cavalo revealed the absence of allelism (S4 Table). In the allelism test using the F 2 population from the cross CDRK × Amendoim Cavalo (χ 2 = 0.026; p-value = 0.87) inoculated with race 3481, a segregation ratio of 15R:1S was obtained, indicating the presence of two independent dominant genes; one gene is Co-AC [66,32], present in the cultivar Amendoim Cavalo, and the other gene originated in CDRK. The same ratio of 15R:1S was obtained using race 3481 in the cross CDRK × MDRK (χ 2 = 0.022; p-value = 0.88), indicating the action of two dominant genes.…”