Assessment of seed storage protein composition of six Iranian adopted soybean cultivars [Glycine max (L.) Merrill.]

Seed protein quality is an important topic in the production of soybean. The quality of soybean proteins is limited by anti-nutrient proteins and low levels of essential sulfur amino acids. In this study, protein content and solubility of six cultivars were evaluated and seed storage proteins were analyzed using SDS-PAGE and scanning densitometry. The results showed that seed storage protein bands were similar among soybean cultivars. However, concentration of β-conglycinin (7S), glycinin (11S) proteins and related subunits were statistically different among the soybean cultivars. According to the results of this study, 033 and DPX cultivars were characterized by high levels of protein content (42.45 %) and protein solubility (76.58 mg g^-1) respectively. Two cultivars DPX and JK were also identified by high 11S/7S ratio (1.39 and 1.43 % respectively). Besides, the JK was considered by the lowest concentration of 7S protein (20.35 %). The results showed that a significant negative correlation existed between protein content and solubility (r= -0.66). A significant and moderate positive correlation was found between acidic and basic subunits with 11S protein (r= 0.72 and 0.47 respectively). The 11S and 7S proteins also showed positive and negative correlation with 11S/7S ratio (r= 0.70 and -0.85 respectively). On the other hand, acidic subunits were characterized by significant positive and negative relationship with 11S/7S ratio and some anti-nutrients protein respectively. Thereupon, these results suggested that the development of new genotypes of soybean with high level of acidic subunits of 11S protein can be notable in increasing seed storage protein quality in soybean breeding programs.