Effects Of Transgenic Soybean On Soil Microbial And Nematode Community

The rapid development of genetically modified crops has brought huge economic benefits. However, the commercial cultivation of GM crops maked people be worried about, owning to its potential adverse effects. Therefore, the ecological security evaluation of GM crops, especially for the effects of GM crops on non-target soil organisms, was imperative. In this study, we compared the effects of three soybean varieties non-transgenic soybean Z13(Z13), stacked traits transgenic soybean ZB (ZB) and herbicide tolerance soybean GTS40-3-2(GTS) on soil microbial community and soil nematode community based on a two-year’s pot experiment. Denaturing gradient gel electrophoresis technique (DGGE) was conducted to study soil microbial community. Nematodes were extracted by Baermann tray technique and identified to genus level using an inverted compound microscope. Nematode indices and multivariate analysis were also used to study nematode communities.The main results during our two-year’s pot investigation were as follows:(1)The effects on soil microbial communitiesDGGE profiles showed:soil microbial communities were abundant under three soybean varieties planting. Cluster analysis suggested that the similarity of soil microbial communities under three soybean varieties planting were more than70%, indicating that compared to Z13, stacked traits transgenic soybean ZB and herbicide tolerance soybean GTS had no effect on soil microbial communities(2)The effects on soil nematode communities①In this study,30soil nematode genera were identified, including15bacterivores,3fungivores,6plant parasites and6omnivore-carnivores.②Compared to Z13, stacked traits transgenic soybean ZB and herbicide tolerance soybean GTS had no effects on soil nematode communities. ZB temporality and significantly decreased the relative abundances of Ba and Om-Ca, H’ and MI, increased But the relative abundances of Fu. GTS temporality and significantly increased the relative abundances of Om-Ca and TD, decreased the relative abundances of PP. These magnititude of such transient effects were markedly less than that caused by sampling time.③Nematode faunal analysis show that all plots moved from A and B quadrant to C and D quadrant, indicating that soil food webs were trending to maturity and similar with progressing duration of the pot experiment. ④Multivariate analysis on the nematode community data revealed that sampling time significantly influence the community structure pattern of nematodes, the community structure pattern of nematodes of stacked traits transgenic soybean ZB and herbicide tolerance soybean GTS were significantly different from non-transgenic soybean Z13. Aphelenchoides, Heterodera and Eucephalobus were the main contribution species of this difference.In summary, no significant different was found between GM soybean and non-GM soybean on soil microbial community and soil nematode community. However, the interaction of GM soybeans and soil ecosystem was a long-term process and are also environmental and biological context dependent. Thus, the long-term monitoring from the view of the entire soil food web would be necessary to clarify whether GM soybeans pose ecological risk to soil ecosystem or not.