Caracterização de regiões genômicas que flanqueiam os locos de resistência à antracnose do feijoeiro-comum co-4 e co-5

Abstract

The common bean (Phaseolus vulgaris L.) is a legume of great importance in the diet of the population, being grown both by small and big farmers throughout the year. The influence of biotic and abiotic factors causes severe losses in yield and quality of the beans. Anthracnose is considered one of the 10 most important fungal diseases in plants. Thus, it is a priority for breeding programs the development of molecular strategies that enable the acceleration and efficiency of the selection of plants resistant to common bean anthracnose. The aim of this study was to characterize markers for the presence of SSRs and SNPs in a region approximately 100kb flanking the target loci of resistance to anthracnose Co-4 and Co-5. 15 common bean genotypes were analyzed, 12 resistant and three susceptible to anthracnose. Altogether, 10 regions SSRs were identified and genotyped for the Co-4 and Co-5 loci. Of the 10 SSRs, five were polymorphic and resulted in identification of 2.8 alleles per locus, genetic diversity and genetic distance averaged 0.3343 and 0.41, respectively. The featured SSRs did not allow discrimination of resistant and susceptible genotypes. The search for genetic regions approximately 100 Kb flanking the target locus resulted in the identification of five putative disease resistance genes annotated as encoding protein kinase. The identified putative genes sequencing was conducted with 15 genotypes of common bean totaling 7,857 bp. 99 SNPs were identified from the sequence alignment, with an average of one SNP every 79 bp. Of this total, 36 were transitions, 57 transversions and six indels. The total nucleotide diversity (θ) was 0.005127. Altogether, 60 SNPs were identified in coding regions, with 22 classified as synonymous and 38 non-synonymous mutations. In addition to the analysis of SNPs, also five primers with potential for use as STS markers were identified for the characterization of putative genes for resistance to anthracnose in common bean. The results obtained in this study are an initial step in the development of molecular markers that allow the identification of associations between haplotypes and phenotypes of tolerance to anthracnose.