Rhizosphere soil metabolites mediated microbial community changes of Pinus sylvestris var. mongolica across stand ages in the Mu Us Desert

Soil metabolites strongly affect microbial community structure and function. Yet the response of soil microbial communities to plant rhizosphere metabolism and their interaction mechanism is poorly understood. In this study, we aimed to explore the influence of Pinus sylvestris var. mongolica (P. sylvestris) rhizosphere metabolites on microbial diversity, and clarify the dominant factors driving the variation in the rhizosphere microbial community along chronosequence. Gas chromatography–mass spectrometry (GC–MS) and high-throughput sequencing were used to determine the rhizosphere metabolites and microbial community composition, respectively. The results showed that P. sylvestris can release a variety of rhizosphere metabolites (such as fatty acids, monoacylglycerides, and diterpenes) with certain ecological functions, and these metabolites significantly affected the rhizosphere microbial alpha diversity and community composition. Simultaneously, the edaphic factors, such as pH, soil moisture, organic carbon, total phosphorus, NO3−-N, NH4+-N, and available phosphorus concentrations, also significantly affected the rhizosphere microbial community. However, partial Mantel test and variation partitioning analysis confirmed the rhizosphere metabolites had a stronger relationship with the variation of rhizosphere bacterial and fungal communities than edaphic factors. Overall, our study highlights the regulatory role of the rhizosphere metabolites of P. sylvestris in shaping microbial community, and provides an insight into the rhizosphere microecological during vegetation restoration process in the Mu Us Desert.