The Distribution and Turnover of Bacterial Communities in the Root Zone of Seven Species Across an Arid and Semi-arid Steppe.

The bacterial communities of the root-zone soil are capable of regulating vital biogeochemical cycles and the succession of plant growth. as grassland constructive species is restricted by the difference features of east-west humidity and north-south heat, which shows the population substituting distribution. The distribution, turnover, and potential driving factors and ecological significance of the root-zone bacterial community along broad spatial gradients of taxa transition remain unclear. This paper investigated seven species root-zone soils based on high-throughput sequencing combined with the measurements of multiple environmental parameters in arid and semi-arid steppe. The communities of soil bacteria in root zone had considerable turnover, and some regular variations in structure along the taxa transition are largely determined by climatic factors, vegetation coverage, and pH at a regional scale. Bacterial communities had a clear population specificity, but they were more strongly affected by the main annual precipitation, which resulted in a biogeographical distribution pattern along precipitation gradient, among which , and were the phyla that were most abundant. During the transformation of taxa from east to west, the trend of diversity shown by bacterial community in the root zone decreased first, and then increased sharply at , which was followed by continuous decreasing toward northwest afterwards. However, the richness and evenness showed an opposite trend, and α diversity had close association with altitude and pH. There would be specific and different bacterial taxa interactions in different species, in which had the simplest and most stable interaction network with the strongest resistance to the environment and had most complex and erratic. Moreover, the bacterial community was mainly affected by dispersal limitation at a certain period. These results are conducive to the prediction of sustainable ecosystem services and protection of microbial resources in a semi-arid grassland ecosystem.