The Research About Ecological Impacts Of EPSPS Transgenic Herbicide-resistant Soybean On Soil Prokaryotic Microorganism Group

With the development of plant transgenic technology, this technology has been widely applied in the agriculture field. Since 1996, the first variety of Roundup Ready soybean was approved for commercial cultivation, the acreage of genetically modified soybean increased year by year, and the vast majority of transgenic soybeans were herbicide-tolerant. Although the genetically modified soybeans give human enormous economic and social benefits, its security issues also attracted worldwide attention, especially to its effects on soil ecosystem. Soil microorganisms can sensitively reflect external interference, and the exogenous genes and expression products of GM soybean can inevitably accumulate in soil, so it could probably have an impact on soil microbes, especially on nitrogen fixation microbial communities.Experimental soybeans and planting places:The EPSPS transgenic herbicide-tolerant soybeans NZL06-698, its receptor soybeans Mengdou 12 and regional control soybean Heihe 43, were planted in Inner Mongolian. The EPSPS transgenic herbicide-tolerant soybeans NZL06-698, its receptor soybeans Mengdou 12 and regional control soybean 2001-311-16, were planted in Jilin province. The EPSPS transgenic herbicide-tolerant soybeans ZJU 31, its receptor soybeans Huachun 3 and regional control soybean Zhonghuang 13, were planted in Anhui province.Research contents:We measured soil physical and chemical properties, nitrogen content, soil carbon and nitrogen cycling-related enzyme activity of soil at different soybean root zone, we also measured soil nitrogen-fixing bacteria diversity, nodulation effect of the nitrogen-fixing bacteria group, and nitrogen-fixing bacteria abundance of different soybean samples’rhizosphere soil. Besides, high-throughput sequencing of 16S rDNA (V4) amplicons has been performed for the rhizosphere microbes of NZL06-698 and its receptor soybeans Mengdou 12 which are planted in Jilin province.Results:1. The experimental data of Inner Mongolian samples show that there are significant differences on soil N content, cultivable nitrogen fixing bacteria diversity and nitrogen-fixing bacteria abundance which is characterized by the abundance of nifH gene, between the EPSPS transgenic herbicide-tolerant soybeans NZL06-698 and its receptor soybeans Mengdou 12. And the abundance of soil nitrogen-fixing bacteria decreased in by planting NZL06-698.2. The experimental data of Jilin province samples show that there are significant differences on soil N content, seeds N content, cultivable nitrogen fixing bacteria diversity and nitrogen-fixing bacteria abundance which is characterized by the abundance of nifH gene, between the EPSPS transgenic herbicide-tolerant soybeans NZL06-698 and its receptor soybeans Mengdou 12. In addition, high-throughput sequencing of 16S rDNA amplicons data shows that the total microorganisms abundance and evenness degree of rhizophere soil increased, but the nitrogen-fixing bacteria abundance of rhizosphere soil decreased by planting NZL06-698.3. The experimental data of Anhui province samples show that there are significant differences on soil nitrogenase activity and cultivable nitrogen-fixing bacteria diversity between the EPSPS transgenic herbicide-tolerant soybeans ZJU 31 and its receptor soybeans Huachun 3. Besides, there are significant differences on the activity of soil nitrate reductase, nitrite reductase, soil nitrogenase enzyme, invertase, between ZJU 31 and ZJU 31 Doses 1. But the results need to be verified by subsequent experiments.Conclusion:Based on the above data analysis, the cultivation of the EPSPS transgenic herbicide-tolerant soybeans or spraying glyphosate may have some impact on microbial communities of rhizosphere soil, especially on nitrogen-fixing bacteria group of rhizosphere soil.