Effects of interactions between arbuscular mycorrhizal fungi and bacteria on the growth of Lotus corniculatus L.: From the perspective of regulating rhizosphere fungal community

Arbuscular mycorrhizal fungi (AMF) provide essential nutrients to crops and are affected by fertilizers. Phosphate solubilizing bacteria (PSB), nitrogen fixing bacteria (NFB), and AMF have a mutually beneficial relationship with plants, but the effects of their interactions on plant growth by regulating rhizosphere fungal community have not been sufficiently studied. In this study, a greenhouse pot experiment was conducted to investigate the interaction between AMF and bacteria (PSB and NFB). Specifically, the role of rhizosphere fungal community in the growth of Lotus corniculatus L. was explored using Illumina MiSeq high-throughput sequencing. The result showed that combined inoculation of AMF, PSB, and NFB increased plant biomass, height, and colonization rate. The richness, complexity, and stability of the rhizosphere fungal community also increased after combined inoculation with AMF, PSB, and NFB, particularly in the AMF + PSB treatment. In addition, combined inoculation of AMF, PSB, and NFB enriched the abundance of beneficial microorganisms, with Chaetomium and Humicola showing the greatest alterations following treatments. The structural equation model (SEM) showed that the interaction between AMF, PSB, and NFB promoted plant growth by affecting the network structure and enzyme activities involved in the Carbon (C), nitrogen (N), and phosphorus (P) cycles of fungal communities. These findings provide evidence for the interaction of AMF, PSB and NFB as well as the influence of fungal community on plants.