Effects of Copper Pollution on Microbial Communities in Wheat Root Systems

Abstract

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.