Characteristics of Phyllosphere and Rhizosphere Bacterial Communities in Bothriochloa ischaemum in Copper Tailings

The phyllosphere and rhizosphere of plants and their living environment jointly form a complex ecosystem. Rhizosphere microorganisms are also the main driving force of the circulation of soil materials, which can provide a basis for the growth and development of plants. Phyllosphere and rhizosphere microorganisms can also be used as ecological indicators, and play significant roles in the ecological stability and recovery of mining areas. In this study, we selected a dominant species, Bothriochloa ischaemum, as the research object. We studied the characteristics of phyllosphere and rhizosphere bacterial communities in B. ischaemum from copper tailings with high-throughput sequencing methods. We explored the key ecological factors affecting the structure and diversity of phyllosphere and rhizosphere bacterial communities in B. ischaemum. The results showed that there were significant differences in the bacterial community structures between the rhizosphere and phyllosphere. The dominant phyllosphere bacterial genera of B. ischaemum included Pseudomonas, Enterobacter, and Sphingomonas. The dominant rhizosphere bacterial genera were Acidibacter and Solrubrobacter. Moreover, the Shannon diversity, abundance-based coverage estimator (ACE), and Chao1 indices of rhizosphere bacterial communities were significantly higher than those of phyllosphere communities. The key ecological factors affecting the dominant phyllosphere and rhizosphere bacterial genera included soil water content, pH, soil arsenic and zinc, total nitrogen, and sulfur of B. ischaemum, as well as plant cadmium and chromium. Furthermore, the Shannon diversity indices of rhizosphere bacterial communities were negatively correlated with root copper contents, and Simpson indices were positively correlated with root total nitrogen. There was a significant positive correlation between the ACE index and leaf total sculpture. These results provide a scientific basis for the exploration and utilization of phyllosphere and rhizosphere bacterial resources, and could improve the efficiency of ecological restoration in copper tailings.