不同生育期转基因抗虫棉根际土壤细菌群落特征

为深入理解转Bt基因抗虫棉对根际土壤微生物群落的影响，基于大田试验，采用高通量测序技术，研究了不同生育期(播种前期、苗期和吐絮期)转基因抗虫棉和亲本根际土壤微生物群落组成和多样性.结果表明:①转基因抗虫棉及亲本根际土壤优势菌门均为变形菌门(Proteobacteria，相对丰度为0.433 8~0.499 3)、拟杆菌门(Bacteroidetes，相对丰度为0.106 0~0.136 6)、放线菌门(Actinobacteria，相对丰度为0.074 9~0.146 4)、芽单胞菌门(Gemmatimonadetes，相对丰度为0.054 2~0.072 3)、酸杆菌门(Acidobacteria，相对丰度为0.053 8~0.089 9).不同生育期转基因抗虫棉对根际土壤细菌优势菌门相对丰度产生显著影响(P < 0.05).②不同生育期转基因抗虫棉与亲本根际土壤细菌群落的Shannon-Wiener指数、Simpson指数、Sobs指数、PD指数均无显著差异(P>0.05)，但PCoA分析发现，苗期和吐絮期转基因抗虫棉和亲本的土壤微生物群落出现空间分异(P < 0.05).③转基因抗虫棉根际土壤Bt蛋白含量在不同生育期具有显著差异(P < 0.05)，且苗期和吐絮期转基因抗虫棉根际土壤Bt蛋白含量显著高于亲本(P < 0.05).④根际土壤Bt蛋白含量与细菌优势菌门相对丰度呈显著相关(P < 0.05).研究显示，不同生育期转基因抗虫棉通过根际Bt蛋白对土壤细菌相对丰度及群落结构产生影响，但不影响土壤细菌的alpha多样性. 

Characteristics of Bacterial Community of Rhizosphere Soil of Transgenic Insect-Resistant Cotton at Different Growth Stages

In order to understand the effect of transgenic Bacillus thuringensis (Bt) cotton on rhizosphere soil microbial community, based on field experiments, high-throughput sequencing technology was used to study the composition and diversity of transgenic and non-transgenic cotton rhizosphere soil microbial community at different growth stages (pre-sowing, seedling and boll-opening stages). The results showed that the dominant phylum in rhizosphere soil of transgenic cotton and its parents were Proteobacteria (0.4338-0.4993), Bacteroidetes (0.1060-0.1366), Actinobacteria (0.0749-0.1464), Gemmatimonades (0.0542-0.0723), Acidobacteria (0.0538-0.0899). The relative abundance of dominant phylum in rhizosphere soil was significantly affected by transgenic cotton at different growth stages (P < 0.05). There were no significant differences in Shannon-Wiener, Simpson, Sobs and PD indices between transgenic cotton and its parents at different growth stages (P>0.05), but PCoA analysis showed that the soil microbial communities of transgenic cotton and its parents had spatial differences at seedling and boll opening stages (P < 0.05). The Bt protein content in rhizosphere soil of transgenic cotton was significantly different at different growth stages, and the Bt protein content in rhizosphere soil of transgenic cotton was significantly higher than that of its parents at seedling stage and boll opening stage. The Bt protein content of rhizosphere soil was significantly related to the relative abundance of bacterial phylum level. The Bt protein in rhizosphere soil of transgenic cotton was significantly correlated with the relative abundance of dominant phylum (P < 0.05). The Bt protein in the rhizosphere of transgenic cotton at different growth stages affected the relative abundance and community structure of soil bacteria, but did not affect alpha diversity.