抗真菌转基因水稻秸秆降解对土壤细菌数量及多样性的影响

Effects of straw decomposition of antifungal transgenic rice on the amount and diversity of soil bacteria

【背景】随着转基因作物的大面积种植,其潜在的环境安全性问题备受关注。转基因作物收获后,大部分残留物会重返土壤,可能对土壤微生物造成影响。【方法】通过室内模拟田间秸秆降解试验,采用平板计数法、表面荧光显微镜直接计数法(FDC)以及变性梯度凝胶电泳(DGGE)技术,分析了抗真菌转基因水稻秸秆降解对土壤细菌数量及多样性的影响。【结果】平板计数表明,在整个降解过程中,转基因与非转基因处理土壤可培养细菌数量的变化趋势有所差别,但差异不显著。FDC结果表明,转基因与非转基因处理土壤细菌总数差异不显著。DGGE指纹图谱显示,转基因与非转基因处理土壤样品之间的多样性指数、均匀度和丰富度均无显著差异。【结论与意义】抗真菌转基因水稻秸秆降解并未对土壤细菌数量和多样性产生显著影响。本研究为抗真菌转基因水稻的环境安全性评估提供了依据。

[ Background] The release of genetically modified crops into environment has become a public concern due to their poten- tial environmental risks. Most of the residues of genetically modified crops will decompose in the soil, which may have an impact on soil microbes. [ Method ] Classical plate counting, epifluoreseenee direct counting method （FDC） and denatured gradient gel elec- trophoresis （DGGE） were employed to analyze the amount and diversity of soil bacteria, during the decomposition of antifungal transgenic rice straw under simulated field conditions. [ Result ] Traditional culture-depending method indicated little difference in the trend of culturable bacterial number during the straw decomposition among all soil treatments ; there was no significant difference between transgenic and non-transgenic treatments. FDC did not indicate significant difference in total bacterial number between transgenic and non-transgenic treatments. DGGE fingerprints also failed to indicate significant differences in the Shannon-Wiener in- dex, evenness and abundance of soil samples between transgenic and non-transgenic treatments. [ Conclusion and significance ] Straw of antifungal transgenic rice did not seem to have significant detrimental or positive effects on the amounts and diversity of bacteria dur- ing decomposition. This study could contribute to the environmental risk assessment of transgenic rice resistant to fungal diseases.