CP4-EPSPS protein expression levels in samples
The expression levels of the CP4-EPSPS gene in plant leaf samples were assessed during different growth stages of soybean. The results showed that all wild soybean samples and SS plants were negative for EPSPS expression. In contrast, EPSPS was detectable at different stages in F1, F2 RR, F2 RS, F3 RR, F3 RS, and GM plants, and the protein levels in both hybrids and GM soybean were influenced by growth stages. The expression of EPSPS declined significantly as plants matured (Fig. 3). The levels of EPSPS in GM plants ranged between 364.28 and 747.79 μg g-1; in F2 plants, they ranged between 124.15 and 247.89 μg g-1, and the protein levels were highest in the R2 stage (230.07 μg g-1) and lowest in the R7 stage (74.29 μg g-1) in F3. In addition, similar levels of relative EPSPS expression were observed for F2and F3 RR and RS plants, and there were no significant differences between RR and RS in different plant generations.