Microbial inoculants stimulate plant secretion of metabolites to recruit soil microbial communities for growth promotion

Microbial inoculants play an important role in mine rehabilitation. However, further investigation is required to understand their effects on soil microbial communities at the metabolic level. In this study, we employed amplicon sequencing and UPLC-MS/MS techniques to examine the response of soil microbial communities and soil metabolic functions to microbial inoculants. Our findings indicate that microbial inoculants significantly influenced the diversity and community structure of both bacterial and fungal communities. Network analyses revealed that microbial inoculants enhanced the stability and complexity of bacterial co-occurrence networks while reducing those of fungal networks. Additionally, microbial inoculants increased the importance of stochastic processes in community assembly, particularly within fungal communities. Metabolomic analyses showed that microbial inoculants significantly altered soil metabolic profiles and functions, up-regulating various metabolic pathways. Correlation analyses further revealed a close relationship between microorganisms and metabolite accumulation. Overall, this study demonstrates that microbial inoculants profoundly impact rhizosphere microbial communities and metabolites. These interactions offer valuable insights into the complex biological processes influenced by microbial inoculants in the rhizosphere.