The microbial gene diversity along an elevation gradient of the Tibetan grassland

Abstract

Tibet is one of the most threatened regions by climate warming, thus understanding how its microbial communities function may be of high importance for predicting microbial responses to climate changes. Here, we report a study to profile soil microbial structural genes, which infers functional roles of microbial communities, along four sites/elevations of a Tibetan mountainous grassland, aiming to explore the potential microbial responses to climate changes via a strategy of space-for-time substitution. Using a microarray-based metagenomics tool named GeoChip 4.0, we showed that microbial communities were distinct for most but not all of the sites. Substantial variations were apparent in stress, N and C-cycling genes, but they were in line with the functional roles of these genes. Cold shock genes were more abundant at higher elevations. Also, gdh converting ammonium into urea was more abundant at higher elevations, whereas ureC converting urea into ammonium was less abundant, which was consistent with soil ammonium contents. Significant correlations were observed between N-cycling genes (ureC, gdh and amoA) and nitrous oxide flux, suggesting that they contributed to community metabolism. Lastly, we found by Canonical correspondence analysis, Mantel tests and the similarity tests that soil pH, temperature, NH 4 þ -N and vegetation diversity accounted for the majority (81.4%) of microbial community variations, suggesting that these four attributes were major factors affecting soil microbial communities. On the basis of these observations, we predict that climate changes in the Tibetan grasslands are very likely to change soil microbial community functional structure, with particular impacts on microbial N-cycling genes and consequently microbe-mediated soil N dynamics.

A hollow bacterial diversity pattern with elevation in Wolong Nature Reserve, Western Sichuan Plateau

“…When the environmental parameters were considered individually, TN was found significantly correlated with bacterial community, which is agree with the result observed on Mt. Shegyla along elevations , suggesting nitrogen could affect the elevational distribution patterns of soil bacteria via determining the metabolism of soil bacteria (Yang et al 2014). As the most important feature in determining bacterial distribution in our study, soil pH generally found to be the most important identifiable factor controlling soil bacterial diversity.…”

“…The study of elevational gradients in montane ecosystem has long been a source of fascination for ecologists (Brown 2001;Korner 2007;Yang et al 2014). Studies of distribution of species and communities have led to a hot research on vertical distribution patterns of macroorganisms (McCain 2005(McCain , 2009Rahbek 2005).…”

Altitudinal Distribution Patterns of Soil Bacterial and Archaeal Communities Along Mt. Shegyla on the Tibetan Plateau

“…And pH-driven diversity patterns were observed horizontally [6] as well as along the elevational gradient [38]. As the fundamental energy sources and component elements for microorganisms, soil organic material and nitrogen also significantly affected the elevational distribution patterns of soil microbes via determining the metabolism of soil microbes [39]. In addition to the edaphic factors, climatic scenarios on the Tibetan Plateau should also be an important consideration.…”

Microbial mediation of biogeochemical cycles revealed by simulation of global changes with soil transplant and cropping

“…In brief, microarray slides were hybridized at 45 1C for 16 h with 50% formamide on a MAUI hybridization station (BioMicro, Salt Lake City, UT, USA) and then scanned with a ScanArray 5000 microarray analysis system (Packard BioChip Technologies, Billerica, MA, USA), as previously described (Yang et al, 2013(Yang et al, , 2014.…”