抗草甘膦转基因大豆对根际土壤细菌及根瘤菌的影响

转基因大豆是全球种植最广泛的转基因作物,抗除草剂是其最主要的转基因特性.微生物群落是土壤质量的监测指标之一,抗草甘膦转基因大豆及配施草甘膦是否影响大豆根际土壤细菌及根瘤菌群落尚不清楚.本研究基于大田试验,以非转基因亲本大豆‘中豆32’为对照(CK),分析转G10-epsps基因耐除草剂大豆SHZD32-01(GR)及配施草甘膦(GR+G)在大豆各生育时期对根际土壤细菌和根瘤菌的影响.结果表明: 与CK相比,GR、GR+G处理对苗期和成熟期根际土壤pH、总有机碳(TOC)、总氮(TN)、NH₄⁺-N含量等产生影响;GR处理显著增加结荚期根际土壤细菌群落丰度及多样性,GR+G处理显著增加结荚期根际土壤细菌群落多样性,但显著降低苗期和结荚期根际土壤细菌群落丰度;GR、GR+G处理改变了部分优势细菌类群的相对丰度,但不同生育期根际土壤优势细菌类群均为变形菌门、酸杆菌门、拟杆菌门、绿弯菌门、浮霉菌门和放线菌门;GR、GR+G处理改变了根瘤菌类群的相对丰度,但未影响慢生根瘤菌和中华根瘤菌两种主要大豆根瘤菌的相对丰度,且GR+G处理结荚期根际土壤根瘤菌相对丰度显著降低.环境因子分析显示,根际土壤放线菌和根瘤菌群落丰度主要受土壤pH影响.抗草甘膦转基因大豆或配施草甘膦显著影响结荚期根际土壤细菌和根瘤菌,但其影响随大豆的生长而消失.

Effects of glyphosate-resistant transgenic soybean on soil rhizospheric bacteria and rhizobia.

Transgenic soybean is the most widely grown genetically modified crop in the world, with herbicide resistance being the major modified trait. Microbial community is one of the most important indicators for soil quality. The effects of glyphosate-resistant transgenic soybean and glyphosate application on rhizospheric bacteria and rhizobia still remained unknown. In this study, with the non-transgenic parent Zhongdou 32 as control (CK), we investigated the effects of the G10-epsps transgenic glyphosate-resistance soybean SHZD32-01 without or with glyphosate application (abbreviated as GR and GR+G, respectively) on rhizospheric bacteria and rhizobia at different growth stages of soybean in field. Compared with CK, GR and GR+G had effects on soil pH, total organic carbon, total nitrogen and ammonium contents at the seedling and mature stages. GR significantly increased the abundance and diversity of soil rhizospheric bacterial community at the podding stage. GR+G significantly increased the abundance of soil rhizospheric bacterial community at the podding stage but decreased its diversity at the seeding and podding stages. GR and GR+G changed the relative abundance of dominant bacteria populations. Proteobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, Planctomycetes and Actinobacteria were generally the dominant ones among the three treatments across all growth stages. Furthermore, GR and GR+G changed the relative abundance of rhizobia but did not change that of soybean-nodulating rhizobia, Bradyrhizobium and Sinorhizobium. The relative abundance of rhizobia in GR+G was decreased significantly at the podding stage. The abundance of actinobacteria and rhizobia was mainly affected by soil pH. Glyphosate-resistant transgenic soybean without or with glyphosate application altered soil rhizospheric bacteria and rhizobia at the podding stage, but the effects disappeared along with the growth of soybean.