Sequence-based DNA marker for simultaneous genotyping of all three β-conglycinin subunit genes in soybean

Soybean (Glycine max [L.] Merr.) seed is about 40% protein, most of which is accounted for by the major storage proteins beta-conglycinin (7S globulin) and glycinin (11S globulin). beta-conglycinin, which consists of three subunits, alpha, alpha', and beta, is the main allergen in soybean. Accordingly, elimination of beta-conglycinin from seed is one of the goals of soybean breeding programs. Soybean accessions PI 200485 and CS 1150 lack the alpha'- and alpha-subunits of beta-conglycinin, respectively. In this study, we developed a 3-betacon marker that could simultaneously identify genotypes for the three subunit genes of beta-conglycinin. Interestingly, the three subunit genes were amplified with three distinct bands representing varied amplicon sizes. Mutant alleles could be identified in progeny of a three-way cross, and the corresponding alpha- and alpha'-subunit proteins were clearly absent in each mutant accession. 3-betacon marker will be highly useful for soybean breeding programs to develop soybean cultivars with decreased beta-conglycinin contents.