A Dominant Locus, qBSC-1, Controls β Subunit Content of Seed Storage Protein in Soybean (Glycine max (L.) Merri.)

Soybean seed storage protein is one of the most important plant vegetable proteins, and β subunit is of great significance to enhance soybean protein quality and processing property. F2 segregated population and residual heterozygous lines (RHL) derived from the cross between Yangyandou (low level of β subunit) and Zhonghuang 13 (normal level of β subunit) were used for mapping of β subunit content. Our results showed that β subunit content was controlled by a single dominant locus, qBSC-1 (β subunit content), which was mapped to a region of 11.9 cM on chromosome 20 in F2 population of 85 individuals. This region was narrowed down to 2.5 cM between BARCSOYSSR_20_0997 and BARCSOYSSR_20_0910 in RHL with a larger population size of 246 individuals. There were 48 predicted genes within qBSC-1 region based on the reference genome (Glyma 1.0, Williams 82), including the two copies of β subunit coding gene CG4. An InDel marker developed from a thymine (TT) insertion in one copy of CG4 promoter region in Yangyandou cosegregrated with BARCSOYSSR_20_0975 within qBSC-1 region, suggesting that this InDel marker maybe useful for marker-assisted selection (MAS).