Characteristics of bacterial biodiversity and community structure in non-rhizosphere soils along zonal distribution of plants within littoral wetlands in inner Mongolia, China

The littoral ecotone between land and lake makes an important part of the lake ecosystem which provide essential ecosystem services for human society. In this paper, the littoral wetland zone of Balagasi Lakeshore, Inner Mongolia, China and steppe being adjacent to was taken as the research object to discuss the characteristics of bacterial diversity and community structure in non-rhizosphere soils along zonal distribution of plants in the arid area. From the sediment of the exposed lakebed to the landward, according to the distribution of plant communities (Phragmites australis, Kalidium foliatum, Achnatherum splendens, Reaumuria songarica and Stipa klemenzii), the relationship between plant communities and soil physical and chemical factors were analysed. The Illumina HiSeq high-throughput sequencing method was used to measure bacterial community diversity and composition in their non-rhizosphere soils along the zonal distribution of plant. The results showed that the distribution of plant communities in the littoral zone of Balagasi Lake was mainly affected by soil bulk density, pH, TP, AP, TOC and TN. Meanwhile, the distribution of bacterial communities in non-rhizosphere soils was mainly affected by water content, salinity, AP, TOC, TP of soils. The communities of Achnatherum splendens, Reaumuria songarica, Stipa klemenzii were negatively correlated with pH, water content and nutrient content, while the Phragmites australis was opposite. There was a positive correlation between the Kalidium foliatum community and soil nutrient content. The species diversity of soil bacteria was the lowest in lakebed sediment. There was a significant negative correlation between Acidobacteria∖Verrucomicrobia∖Actinobacteria and soil salinity, so in the three sample groups near the lakebed area (lakebed sediment, Phragmites australis community, Kalidium foliatum community), the relative abundance of which was lower than slope and landward terrace. However, the relative abundance of Proteobacteria was opposite. Bacteroidetes was positively correlated with soil nutrients, and its relative abundance was the highest in the non-rhizosphere soil of Kalidium foliatum community with the highest soil nutrients.