Assessment of the effect on soil microbial communities of genetically modified soybean and a hybrid from crossing with wild soybean

Microbial community analysis of the rhizosphere is one of many approaches for evaluating the environmental impact of genetically modified (GM) crops. To elucidate the influence of GM and hybrid soybeans on the bacterial community of the rhizosphere, this study used a beta-carotene-enhanced transgenic soybean as the GM crop, modified from Kwangan soybean (Glycine max (L.) Merrill), and a hybrid soybean line in which this GM soybean line had been crossed with wild soybean (Glycine soja). Bacterial community analysis indicated that compared to their non-transgenic counterpart, there were no significant effects on the rhizospheres of either the GM or hybrid soybeans. The bacterial densities of the rhizosphere of hybrid and GM soybeans were found to be within the range of those of non-GM soybeans. We found no horizontal gene transfer from GM and hybrid soybeans to soil rhizosphere microorganisms by PCR analysis. Therefore, our results suggest that the impact of GM and hybrid soybeans on the environment, especially on soil microorganisms, is insignificant.