Objective The purpose of this study was to explore the expression differences of glutamine synthetase (GS) gene family members in 3 types of soybean during growth stages and understand the characteristics of protein formation of soybean with high protein content.

Method GS gene expression quantity and glutamine synthetase activaty (GSA) in root, stem, leaf and root nodul from three tested materials, Glycine max, G. max with high protein content and G. soja with high protein content, were investigated at whole growth stage, respectively.

Result and conclusion The results were two as follows: the expression of each GS gene member in different organs of three types of soybean was obviously different. GSβ1 in root, stem, leaf and root nodules all expressed high. The expression quantity of GS2 in leaf was significantly higher than that of the other two organs and root nodules. The expression of GSγ1 in nodule increased, while the expression of GSγ1 in roots, stems, leaf was very low. The expression quantity of GSβ1 in root, stem, leaf and root nodules in whole growth period, GS2 in leaf, GSγ1 in root no-dule and the general expression quantity of GS genes at V3-R3 stages were higher in high protein soybean variety than those of normally cultivated soybean variety. This variation was consistent with the variational rule of GSA of three types of soybean. Compared with G. max, effectively regulating the expression of GS gene family members and obtaining high GSA in the whole growth period are characteristics of high protein content soybean.