Pyrosequencing investigation into the bacterial communities in the Qinghai-Tibet Plateau soils associated with soil characteristic factors

The Qinghai Tibet Plateau (QTP) is one of the most important regions of the earth’s ecosystem that is vulnerable to climate and human activities due to its complex climate and terrain. However, knowledge about soil bacterial communities and their effect on the ecosystem within the QTP environments is still scarce. Metagenomic approaches on the structure and diversity of bacterial communities and their relationship with the environment from eighteen selected sites of the five major QTP ecosystems (gray-cinnamon soils, chernozems, castanozems, mountain meadow soils, gray desert soils) are presented in this paper. The dominant bacterial phyla in five type soils were Proteobacteria and Actinobacteria, whereas Actinobacteria and Chloroflexi predominated in gray desert soils. The bacteria diversity in castanozeras and mountain meadow soils was significantly higher than that of the other three soil types (P < 0.05). Phylogenetic diversity in gray desert soil was significantly lower than that of other four soil types (P < 0.05). Phylotype richness was the lowest in gray-cinnamon soils. There were significant correlations between the phylotype richness and soil moisture (r = -0.578) and potassium (r = -0.529). Phylogenetic diversity (PD) was significantly correlated with total organic carbon (r = -0.548). The redundancy analysis (RDA) showed that the diversity and composition in the bacterial communities differed greatly among the five soil types and that they were closely correlated with the soil moisture, soil organic carbon and potassium. These results indicated that the bacterial community structures of QTP soils were obviously influenced by soil characteristics and soil environmental characteristics and provided a theoretical basis for the optimal management and sustainable utilization of the QTP soil ecosystem, which is of great significance.