Phylogenetic diversity of stochasticity-dominated predatory myxobacterial community drives multi-nutrient cycling in typical farmland soils

Abstract

Predatory myxobacteria are keystone taxa in the soil microbial food web that potentially regulate soil microbial community structure and ecosystem functions. However, little is known about the community assembly processes of myxobacteria in typical farmland soils over large geographic scales, in addition to their relationship with soil multi-nutrient cycling. Here, we used high-throughput sequencing techniques and phylogenetic null modeling analysis to investigate the distribution patterns and assembly processes of myxobacteria communities, in addition to interactions between myxobacteria communities and soil multi-nutrient cycling. Anaeromyxobacter (28.5 %) and Haliangium (19.6 %) were the dominant myxobacteria genera in all samples, and myxobacteria community similarities exhibited distinct distance-decay relationships. Stochastic processes (~77.8 %) were the dominant ecological processes driving the assembly of predatory myxobacteria communities over large geographical scales and under three fertilization regimes. Myxobacteria community structure was influenced by geographic factors (location and climate), soil factors (soil pH, soil organic carbon, total nitrogen, and total potassium), and fertilization, with myxobacteria community assembly being more sensitive to geographic factors. Organic-inorganic combined fertilization (NPKM) increased the proportions of deterministic processes in myxobacteria community assembly. Moreover, myxobacteria community assembly and diversity were closely associated with soil multi-nutrient cycling. Hence, myxobacteria phylogenetic α-diversity represented by NTI index is a potential bioindicators for soil multi-nutrient cycling. Overall, our findings comprehensively reveal the mechanisms of assembly of myxobacteria communities in soils over large geographic scales, and provide a theoretical basis for further research on the role of predatory bacteria on soil nutrient cycling in agro-ecosystems.