Community structure and elevational diversity patterns of soil Acidobacteria

Acidobacteria is one of the most dominant and abundant phyla in soil, and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational diversity patterns. We selected four elevation gradients from 1000 to 2800 m with typical vegetation types of the northern slope of Shennongjia Mountain in central China. The vegetation types were evergreen broadleaved forest, deciduous broadleaved forest, coniferous forest and sub-alpine shrubs. We analyzed the soil acidobacterial community composition, elevational patterns and the relationship between Acidobacteria subdivisions and soil enzyme activities by using the 16S rRNA meta-sequencing technique and multivariate statistical analysis. The result found that 19 known subdivisions as well as an unclassified phylotype were presented in these forest sites, and Subdivision 6 has the highest number of detectable operational taxonomic units (OTUs). A significant single peak distribution pattern (P < 0.05) between the OTU number and the elevation was observed. The Jaccard and Bray-Curtis index analysis showed that the soil Acidobacteria compositional similarity significantly decreased (P < 0.01) with the increase in elevation distance. Mantel test analysis showed the most of the soil Acidobacteria subdivisions had the significant relationship (P < 0.01) with different soil enzymes. Therefore, soil Acidobacteria may be involved in different ecosystem functions in global elemental cycles. Partial Mantel tests and CCA analysis showed that soil pH, soil temperature and plant diversity may be the key factors in shaping the soil Acidobacterial community structure.