Characterization of soil microbes associated with a grazing-tolerant grass species, Stipa breviflora, in the Inner Mongolian desert steppe

Abstract

Although soil microbial communities are central in ecosystem functioning, we know little of their characterization for those associated with grazing-tolerant host plant species in grassland ecosystems in response to grazing. In this study, we used a high-throughput sequencing approach to characterize soil microbes from the rhizosphere and bulk soil of grazing-tolerant grass species, Stipa breviflora, in the Inner Mongolian desert steppe. We found that response mechanisms of soil bacteria distinct from fungal communities, and variance also occur between the rhizosphere and bulk soil communities under long-term grazing. Soil fungal communities and the co-occurrence networks in S. breviflora rhizosphere were more sensitive to long-term grazing than bacteria. We reveal that rhizosphere effects and soil water content were the main drivers of the changes in fungal communities and their co-occurrence networks. Moreover, the dominant bacterial phyla Bacteroidetes and Proteobacteria and fungal phyla Ascomycota and Glomeromycota might participate in regulating processes of S. breviflora's response to grazing. Overall, these findings give new snapshots of mechanisms of how grazing affects soil microbial communities, in an attempt to contribute to a clearer understanding of grazing-tolerant mechanism of S. breviflora.