Plants exhibit significant effects on the rhizospheric microbiome across contrasting soils in tropical and subtropical China

The rhizospheric microbiome appears to be one of the key determinants of plant health and productivity. In this study, to understand the assembly process of the rhizospheric microbiome, the effects of different sites, soils and plants on the rhizospheric microbiome were compared and examined using high-throughput sequencing. A series of comparisons of rhizospheric microbiomes were conducted using two plants (wild rice (Oryza rufipogon Griff.) and L. hexandra (Leersia hexandra Swartz)), two soils (high nutrient and low nutrient) and two sites (Guangdong and Hainan provinces in China). The results of the redundancy analysis, between-class analysis and coinertia analysis indicated that the factors shaping the rhizospheric microbiome (in decreasing order of strength), were the site, soil and plant. The effects of plants on the rhizospheric microbiome were slight and unobvious, with relatively low-explained variations and few core groups and indicator groups; however, the effects were significant across different sites and soils, especially for specific microbial groups that are closely associated with plants, such as pathogens, symbionts, and saprotrophs. Furthermore, rhizospheric fungi were more strongly influenced by plants than rhizospheric bacteria. Our results provide insights into the relationships among multiple factors that shape the rhizospheric microbiome in natural ecosystems and highlight the effects of plants across regional environmental shifts.