Enhanced Metabolic Potentials and Functional Gene Interactions of Microbial Stress Responses to a 4,100-m Elevational Increase in Freshwater Lakes.

Huabing Li,Qingyun Yan,Lijuan Ren,Jin Zeng,Qinglong L Wu

doi:10.3389/fmicb.2020.595967

Abstract

Elevation has a strong influence on microbial community composition, but its influence on microbial functional genes remains unclear in the aquatic ecosystem. In this study, the functional gene structure of microbes in two lakes at low elevation (ca. 530 m) and two lakes at high elevation (ca. 4,600 m) was examined using a comprehensive functional gene array GeoChip 5.0. Microbial functional composition, but not functional gene richness, was significantly different between the low- and high-elevation lakes. The greatest difference was that microbial communities from high-elevation lakes were enriched in functional genes of stress responses, including cold shock, oxygen limitation, osmotic stress, nitrogen limitation, phosphate limitation, glucose limitation, radiation stress, heat shock, protein stress, and sigma factor genes compared with microbial communities from the low-elevation lakes. Higher metabolic potentials were also observed in the degradation of aromatic compounds, chitin, cellulose, and hemicellulose at higher elevations. Only one phytate degradation gene and one nitrate reduction gene were enriched in the high-elevation lakes. Furthermore, the enhanced interactions and complexity among the co-occurring functional genes in microbial communities of lakes at high elevations were revealed in terms of network size, links, connectivity, and clustering coefficients, and there were more functional genes of stress responses mediating the module hub of this network. The findings of this study highlight the well-developed functional strategies utilized by aquatic microbial communities to withstand the harsh conditions at high elevations.

Highlights

Elevational patterns of biodiversity have attracted interest in the scientific fields of microbial ecology and biogeography because of the importance of these patterns in facilitating a comprehensive understanding of the influences of climate change on ecosystems
17,238 functional genes were detected in the 24 samples, of which 14,912 genes were derived from bacteria, 631 genes were from archaea, 1603 genes were from fungi, and the remaining genes were from bacteriophages
Microbial functional gene overlap between elevations was calculated and revealed that 75.58–87.32% of the genes were shared between the high-elevation lakes (HELs) and low-elevation lakes (LELs) (Figure 1B and Supplementary Table 2)

Summary

Introduction

Elevational patterns of biodiversity have attracted interest in the scientific fields of microbial ecology and biogeography because of the importance of these patterns in facilitating a comprehensive understanding of the influences of climate change on ecosystems. The development of microbial molecular biology technologies has led to considerable attention being directed at the phylogenetic and functional diversity patterns of microbial communities along elevations (Wang et al, 2011; Hayden and Beman, 2016; Li et al, 2017). Most of these studies focused on taxonomy. Elucidating these patterns could improve our understanding of the influences of climate change on microbial-related ecological processes

Methods

Results

Conclusion