铜胁迫对小麦根系微域微生物群落的影响

小麦是我国主要的粮食作物，土壤重金属污染会严重威胁作物生长和粮食安全.大量研究表明根际微生物在调控作物发育和抗逆性方面具有非常重要的作用.因此，本研究通过高通量测序技术研究铜胁迫条件下小麦根际微生物群落的变化，从微生物学角度揭示铜污染胁迫对小麦根际的影响作用.采用盆栽培养试验对铜污染处理中小麦非根际、根际以及根内微生物进行测序后，分别比较小麦不同根系分区环境中的微生物群落结构和多样性.结果发现，所有处理中小麦的根内微生物多样性均显著（P<0.001）低于根际和非根际微生物多样性，表明根表作为微生物进入根内环境的门户，对根内微生物的定殖起着过滤和筛选的作用.铜污染胁迫降低了根际土环境中的微生物多样性，且差异显著（P<0.05）；而在非根际和根内环境中，尽管铜污染胁迫降低了对应根系分区中的微生物多样性，但差异不显著（P>0.05）.变形菌门（Proteobacteria）和放线菌门（Actinobacteria）是小麦根际和非根际环境中的共有优势菌群，通过比较发现铜污染胁迫对这两种优势菌门的影响作用较小.另外，芽孢杆菌属（Bacillus）、假黄色单胞菌属（Pseudoxanthomonas）和鞘氨醇单胞菌属（Sphingomonas）等菌属具有较强的抗逆性，能够在铜污染胁迫下存活且能够为植物提供营养物质.

Effects of Copper Pollution on Microbial Communities in Wheat Root Systems

Wheat is the main food crop in China while at the same time, heavy metals pose a significant threat to crop growth and food security. Many studies indicate that rhizospheric microorganism play an important role in regulating crop development and stress resistance. In this study, the variation in wheat root-associated microbial communities under copper pollution was studied using high-throughput sequencing. The microbial community structure and diversity among different wheat rhizocompartments were compared after sequencing of microbial communities in the bulk soil, rhizosphere, and endosphere of wheat under copper pollution in combination with pot-based experiments. The results showed that the microbial diversity of the endosphere was significantly lower than in the rhizosphere and bulk soil(P<0.001), indicating that root surfaces serve as a gateway for microorganisms to enter into the interior root environment, and play a role in filtering root colonization. Copper pollution significantly reduced the microbial diversity of the rhizosphere (P<0.05). In the bulk soil and endosphere environments, although copper pollution reduced microbial diversity in the corresponding rhizocompartment, the difference was not significant (P>0.05). Proteobacteria and Actinobacteria were the dominant bacteria groups in the rhizosphere and the bulk soil under copper pollution. In addition, microbes such as Bacillus, Pseudoxanthomonas, and Sphingomonas show strong stress resistance and can provide nutrients for plants.