Characterization of the Community Structure of Rhizosphere Soil and Root-endophytic Bacteria in Different Shrubs

Abstract

In the process of ecological restoration, vegetation plays a crucial role in restoring ecosystem functions. Soil microorganisms are essential components of soil ecosystems, driving material cycling processes and enhancing plant productivity and resilience. This study aimed to investigate the community structure characteristics of rhizosphere soil and root-endophytic bacteria in different shrubs. Specifically, the composition of rhizosphere soil and root-endophytic bacteria in Cotoneaster acutifolius Turcz., Lonicera japonica Thunb., and Cornus alba L. in the loess hilly area of northwest Shanxi was determined using Illumina high-throughput sequencing technology. The results revealed that the dominant phyla of rhizosphere soil bacteria and root-endophytic bacteria in different shrubs were Proteobacteria and Actinobacteria. Additionally, the genera of rhizosphere soil and root-endophytic bacteria differed. Furthermore, the species richness and diversity index of rhizosphere soil bacteria were significantly higher than those of root-endophytic bacteria （P < 0.05）. It was also observed that approximately 64% of the root-endophytic bacteria in the shrubs were present in the rhizosphere soil bacteria, indicating similarity in the bacterial community compositions of different niches. Redundancy analysis （RDA） and Pearson correlation analysis revealed that soil dehydrogenase, soil N-acetyl-β-D glucosidase, alkaline protease, pH, and total phosphorus were the main influencing factors on the bacterial community structures in root-endophytic bacteria （P < 0.05）, while alkaline protease, pH, total carbon, and total nitrogen significantly impacted rhizosphere soil community structures （P < 0.05）. Additionally, the partial least squares path model （PLS-PM） indicated that vegetation could directly affect bacterial communities and indirectly affect them by influencing soil physicochemical properties and soil enzyme activity. In conclusion, the findings of this study provide a theoretical foundation for further research on the relationship between endophytic bacteria and resistance in shrubs.