Endophytic bacteria in the periglacial plant Potentilla fruticosa var. albicans are influenced by habitat type

Microbial communities in different plant compartments are relatively independent entities. However, the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear. In this study, we quantified the bacterial communities in the rhizosphere soil, as well as root and leaf endosphere compartments of a periglacial plant, Potentilla fruticosa var. albicans, using high-throughput DNA sequencing. Moreover, we evaluated the impacts of habitat types (glacier terminus zone, moraine ridge, and alpine meadow) on the bacterial community in different plant compartments of Potentilla fruticosa var. albicans. Our results showed that habitat type had a significant effect on the alpha diversity (Chao1 richness) of endophytic bacteria, but not on the rhizospheric bacteria. The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats, and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria. The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow. In contrast, host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow. Furthermore, we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone. The bacterial community was governed primarily by stochastic processes regardless of habitat type. This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var. albicans are more affected by habitat types than that of rhizospheric bacteria. Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var. albicans vary by habitat type. These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.