β-Conglycinin and Glycinin in High-Protein Soybean Seeds

The agronomic performance and storage proteins of high seed protein lines of soybeans [Glycine max L. (Merr.)] were investigated to determine if the two major storage proteins, β-conglycinin and glycinin, contribute to the increased protein content of high seed protein lines. Subunits of these two major storage proteins were estimated by scanning SDS-PAGE gels by scanning densitometry. The relative rankings of the lines with respect to seed size and protein content were not different between years in one environment over 5 years, but oil and total protein and oil contents and the ratio of protein to oil differed. The α', α, and β subunits of β-conglycinin were significantly higher in the high-protein lines except CX797-115, CX804-108, CX804-3, D81-8498, and NC-2-62. The acidic A3 polypeptide of glycinin was significantly higher in high-protein lines except 76-48773, CX804-108, CX804-3, D81-8498, and NC-2-62, whereas the acidic polypeptides A1,2,4 of glycinin were significantly higher in all of the high-protein lines. The basic polypeptides of glycinin were significantly higher in all high seed protein lines except D81-8259. In conclusion, high-protein lines appear to contain more β-conglycinin and glycinin than normal-protein soybean lines, and the amounts of subunits and polypeptides differ among lines. Keywords: Glycine max L. (Merr.); β-conglycinin; glycinin; high-protein seeds; electrophoresis