Characterization of the Microbial Community Structures, Soil Chemical Properties, and Enzyme Activity of Stellera chamaejasme (Thymelaeaceae) and Its Associated Forages in Alpine Grassland of Northwestern China

The invasion of toxic weeds was detrimental to the growth of original vegetation and speed up the degraded grasslands. The purpose of this study was to explore the difference in microbial community, soil physicochemical properties, and enzyme activity in the rhizosphere of Stellera chamaejasme and its associated forages (Stipa purpurea and Polygonum viviparum). The rhizosphere soil microbial communities of S. chamaejasme and its associated forages were determined by high-throughput sequencing technology, the physicochemical properties, and enzyme activities were also measured using soil chemical methods. We performed biological statistical analyses to explore the correlation of rhizosphere micro-ecological environment between the invading poisonous herb S. chamaejasme and its associated forages. The Ascomycota community in the rhizosphere soil of S. chamaejasme was significantly decreased when compared with its associated forages. S. chamaejasme and S. purpurea had a similar bacterial composition, while the rhizosphere of P. viviparum was associated with more Acidobacteria and Bacteroidetes. The RDA analysis showed S. chamaejasme had highly correlated with acid proteinase, invertase, polyphenol oxidase, cellulose, and neutral protease and S. purpurea had highly associated with N-acetyl-beta-D-glucosaminidase, beta-D-Glucosidase, and the P. viviparum had highly associated with total phosphorus, total nitrogen, ammonium nitrogen, soil organic matter, pH, acid phosphatase, and catalase. Along with the invasion of S. chamaejasme, the microbial composition, soil physicochemical properties, and enzyme activity of the growing area changed considerably compared with the associated forages. Taken together, our results suggested that the composition and diversity of microbial communities associated with S. chamaejasme and its associated forages exhibited different patterns, and the rhizosphere soil microbial communities in different plants were regulated by different environmental factors in this alpine grassland ecosystem.