Funneliformis mosseae Enhances the Function of C, N and P Cycling Bacteria in Continuous Soybean Rhizosphere Soil

This study inoculated Funneliformis mosseae (F. mosseae) into continuously cropped soil with the aim of investigating the changes in carbon (C), nitrogen (N), and phosphorus (P) cycling bacteria and functional genes in the soybean rhizosphere soil. It revealed the mechanisms by which Arbuscular Mycorrhizal Fungi (AMF) promote the cycling of C, N, and P by enhancing the diversity and abundance of soil functional bacteria, and explored the correlations between C, N, P cycling bacteria, functional genes, and soil factors. 16S rRNA sequencing and quantitative microbial element cycling (QMEC) were used to identify the variations in soil bacterial community composition and quantitative expression of functional genes. Continuous cropping of soybeans reduced the diversity and relative abundance of bacteria associated with C, N, and P cycling in the rhizosphere soil, as well as the abundance of functional genes such as xylA, acsA, pmoA, nosZ, and pqqC. Inoculation with F. mosseae increased the abundance of functional bacteria such as Actinobacteriota, Proteobacteria, and Bacteroidota, as well as functional genes like rbcL, nirS2, and phoD in the rhizosphere soil of continuously cropped soybeans. Actinobacteriota, Nitrospirota, and Firmicutes were significantly positively correlated with functional genes related to C, N, and P cycling. Additionally, pH, organic matter, and total nitrogen were significantly positively correlated with the abundance of functional genes involved in the cycling of C, N, and P, indicating their importance as environmental factors affecting the abundance of these functional genes. Inoculation with F. mosseae could increase the abundance of C, N and P cycling functional bacteria and functional genes in the rhizosphere soil of continuous cropping soybean, and improved the microbial community structure of continuous cropping obstacle soil.