耐除草剂转基因大豆对根际土壤固氮微生物nifH基因多样性的影响

Effects of herbicide tolerant transgenic soybeans on the diversity of soil nitrogen-fixing bacterial nifH genes in rhizosphere

通过大田试验,以两种耐除草剂转基因大豆(PAT、ALS)及相应非转基因亲本大豆(PAT1、ALS1)和当地主栽大豆中黄13(CK)为材料,采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术及扩增产物序列分析方法,探讨耐除草剂转基因大豆种植对根际土壤固氮微生物nifH基因多样性的影响。结果表明,PAT、ALS与相应亲本大豆PAT1、ALS1相比,根际土壤固氮微生物群落组成相似度均在60%左右。PAT、ALS根际土壤固氮微生物nifH基因多样性指数(H)和均匀度指数(EH)与相应亲本大豆相比差异均不显著(p>0.05)。测序结果表明,PAT、ALS与相应亲本大豆根际土壤中固氮微生物主要隶属于蓝藻门(Cyanobacteria)、变形菌门(Proteobacteria)和厚壁菌门(Firmicutes)。不同处理下nifH基因与理化因子的典范对应分析结果表明,速效磷(AP)、硝态氮(NO3--N)对固氮微生物区系的影响达到显著水平(p<0.05)。以上结论表明,与PAT1、ALS1相比,两种耐除草剂转基因大豆对根际土壤固氮微生物nifH基因多样性的影响不显著。

Based on the polymerase chain reaction - denaturing gradient gel electrophoresis （ PCR - DGGE ） and sequence analysis, two herbicide tolerant genetically modified soybeans （PAT, ALS） and the corresponding non - transgenic soybeans （ PAT1, ALS1 ） and the local main non - transgenic soybean （Zhonghuang 13, CK） were selected to investigate the effects of herbicide tolerant transgenic soybean cultivation on nitrogen -fixing bacteria in rhizosphere under field experiment. The results showed that the community composition similarity of soil nitrogen - fixing bacteria between transgenic soybean （ PAT, ALS） and the corresponding non - trans genic soybean （ PAT1,ALS1 ） was approximately 60%. Compared to the corresponding non - transgenic soybeans （ PAT1, ALS1 diversity index （H） and evenness index （EH） of nitrogen - fixing bacterial n/fl-/genes in rhizoshpere of he , the icide tolerant genetically modified soybeans （PAT, ALS） both showed no significant difference （p 〉 0.05 ）. The sequen- cing and phylogenetic analysis indicated that nitrogen - fixing bacterial n/fH genes in rhizoshpere of herbicide toler- ant genetically modified soybeans （ PAT, ALS） and the corresponding non - transgenic soybeans （ PAT1, ALS1 ） mainly belonged to cyanobacteria, Proteobacteria and Firmicutes. Nitrogen -fixing microbial communities were sig- nificantly （p 〈 0.05 ） influenced by the levels of the available phosphorus （AP） and nitrate nitrogen （NO3 - -N） when canonical correspondence analysis was used to identify relationship between n/fH gene and soil physicochemi- cal factors. This result indicated that herbicide tolerant genetically modified soybeans had no significant effects on the diversity of soil nitrogen - fixing bacterial niftt ~enes in rhizosDhere.