Discovering the Genetic Architecture of Dietary Fiber and Oligosaccharide Content in Common Bean (Phaseolus vulgaris )

Common bean (Phaseolus vulgaris), the most important edible legume, is rich in protein, minerals and vitamins as well as soluble and insoluble fiber. Dietary fiber has many health benefits for humans. These include lowering blood pressure, reducing the risk of advanced colorectal cancer, obesity, diabetes and cardiovascular disease. Common bean also contains some undesirable oligosaccharides such as raffinose, stachyose, and verbascose which cause intestinal discomfort in humans. Thus there is an interest to breed for varieties with higher fiber but lower oligosaccharides. Knowing the genetic architecture underlying these traits in bean can accelerate and facilitate the breeding process. Genome wide association study (GWAS) is an effective method to map the genomic regions responsible for traits of interest in a population of unrelated individuals. GWAS approach coupled with the availability of common bean whole genome sequence could lead to higher resolution mapping and facilitate candidate gene discovery. We used 15,127 SNPs with minor allele frequency of 5% and greater in a population of 263 genotypes from the BeanCAP project to map the fiber and oligosaccharide traits. We were able to identify strong candidate genes for traits soluble and insoluble dietary fiber content and raffinose and stachyose content.