Alterations of the rhizosphere soil microbial community composition and metabolite profiles of Angelica sinensis seedlings by co-application of Nitrogen fixing bacteria and amino acids

Aims Our objective was to examine short-term responses of A.sinensis agronomic, soil productivity to agricultural management (i.e. amino acid (AAs) and nitrogen-fixing bacteria (NFB) as alone or co-applicationed exogenous nitrogen (N) after cover planting). Methods A field experiment was established with four fertilization treatments, including NFB (Y1), NFB and AAs (Y2), AAs (Y3), and sterile water (CK). The plant yield, biomass, N and C content, photosynthesis and the soil chemical properties, microbial community and metabolite spectrum were evaluated. Results Y2 improved the crop biomass by 32–66% than CK, Y1 and Y3. It also decreased soil C/N by 24.29% than CK. 16S rRNA and ITS genes revealed that Y2 markedly enhanced the growth of copiotrophic taxa ( Alloprevotella , Bactriodies and Alistipes ) while inhibiting the growth of oligotrophic taxa ( Sphingomonas and Ellin6055 ), among the dominant bacteria. Y2 reduced the growth of pathogenic taxa ( Thanatephorus and Fusarium ) that are encouraged by AAs. Further, AAs and NFB addition directly affected the diversity of bacteria and fungi and indirectly affected fungal diversity by altering soil total organic carbon (TOC), total nitrogen (TN), C/N. Additionally, soil metabolomics analysis revealed that Y3 elevated the concentration of chemical compounds that impede microbial growth, while decreasing fructose, N-Acetylglutamic acid, and arginine involved in C and N metabolism. Y2 augmented the content of disease-resistant compounds and lysine in N metabolism. Conclusion Inoculating AAs with NFB ( Bacillus amyloliquefaciae and Pseudomonas fluorescence ) is a strategy with immense benefits as a biofertilizer for sustainable A.sinensis production, which also renders soil ecological services.