Rhizosphere microbial community structure in the water-level-fluctuation zone under distinct waterlogging stresses

Abstract

Rhizosphere microbial communities are believed to be vital in the adaption of dominant plants to strong waterlogging stress in the water-level-fluctuation zone (WLFZ). However, limited knowledge is available on their patterns in the WLFZ under distinct waterlogging stresses. Here, rhizosphere and non-rhizosphere bacterial and fungal communities derived from two typical dominant plants (Rumex acetosa L. and Oxybasis glauca) in the WLFZ of Three Gorges Reservoir, China were analysed through high-throughput sequencing. A total of 63 phyla, 173 classes, 259 orders, 287 families and 518 genera of bacteria, as well as 15 phyla, 50 classes, 124 orders, 265 families and 652 genera of fungi were detected in soils with different waterlogging stress intensities. The most dominant bacterial and fungal phyla in each sample are Proteobacteria and Ascomycota, respectively. Bacteria and fungi in soil may increase their microbial ɑ diversity under the intensity of waterlogging stress to cope with this stress. LEfSe analysis showed that the impact of waterlogging stress on fungal community structure in soil is more prominent than that on bacteria. Key fungal biomarkers can be found in each soil sample, but in many samples, key bacterial biomarkers cannot be found. The metabolic pathways related to aerobic respiration type I and de novo biosynthesis of adenosine ribonucleotides dominate in the microbial community. Redundancy analysis revealed that the structure of rhizosphere microbial communities in different plants is significantly influenced by environmental factors. This study provides a theoretical basis for understanding the relationship between plants and their second genome (rhizosphere microorganisms) in extreme habitats, such as the WLFZ of large reservoirs.