Effect of allelochemicals, soil enzyme activity and environmental factors from Stellera chamaejasme L. on rhizosphere bacterial communities in the northern Tibetan Plateau

Allelochemicals exuded by Stellera chamaejasme into the soil environment could be an important factor which might contribute to its competitive behavior in nature. We aimed to explore the interactions between the allelochemicals, soil enzyme activities, environmental factors and rhizosphere bacterial communities which might contribute to the plant's invasiveness. The composition and abundance of rhizosphere soil bacteria communities were examined in five locations in the northern Tibetan Plateau. Actinobacteria and Proteobacteria were dominant in all rhizosphere soil samples and were similar among the bacterial communities. The contents of Actinobacteria showed positive correlations with neochamaejasmin B and mesoneochamaejasmin A, and negative correlations with chamaechromone and 7-methoxylneochaejasmin A. The Principle component analysis (PCA) and Redundancy analysis (RDA) revealed that Streptomycetales activity correlated with the content of neochamaejasmin B and mesoneochamaejasmin A, and Frankiales activity appeared to relate to chamaechromone and 7-methoxylneochaejasmin A. Enzyme activities and environmental factors correlated with the presence of rhizosphere soil bacterial communities. These results suggest that the allelochemicals, soil enzyme activities and the environment, to some extent, affect the composition and diversity of rhizosphere soil bacterial communities. The results provide a better understanding of the allelopathy of S. chamaejasme and its broad ecological adaptability.