Altitudinal distribution patterns of soil bacterial and archaeal communities along mt. Shegyla on the Tibetan Plateau.

Abstract

Unraveling the distribution patterns of plants and animals along the elevational gradients has been attracting growing scientific interests of ecologists, whether the microbial communities exhibit similar elevational patterns, however, remains largely less documented. Here, we investigate the biogeographic distribution of soil archaeal and bacterial communities across three vertical climate zones (3,106-4,479 m.a.s.l.) in Mt. Shegyla on the Tibetan Plateau, by combining quantitative PCR and high-throughput barcoded pyrosequencing approaches. Our results found that the ratio of bacterial to archaeal 16S rRNA gene abundance was negatively related with elevation. Acidobacteria dominated in the bacterial communities, Marine benthic group A dominated in the archaeal communities, and the relative abundance of both taxa changed significantly with elevation. At the taxonomic levels of domain, phylum, and class, more bacterial taxa than archaeal exhibited declining trend in diversity along the increasing elevational gradient, as revealed by Shannon and Faith's phylogenetic diversity indices. Unweighted UniFrac distance clustering showed that the bacterial communities from the mountainous temperate zone clustered together, whereas those from the subalpine cool temperate zone clustered together. However, the partitioning effect of elevational zones on the archaeal community was much weaker compared to that on bacteria. Redundancy analysis revealed that soil geochemical factors explained 58.3 % of the bacterial community variance and 75.4 % of the archaeal community variance. Taken together, we provide evidence that soil bacteria exhibited more apparent elevational zonation feature and decreased diversity pattern than archaea with increasing elevation, and distribution patterns of soil microbes are strongly regulated by soil properties along elevational gradient in this plateau montane ecosystem.