Soil pH is equally important as salinity in shaping bacterial communities in saline soils under halophytic vegetation

Shuai Zhao,Samiran Banerjee,Na Zhou,Jun-Jie Liu,Ke Zhang,Zhen-Yong Zhao,Chang-Yan Tian

doi:10.1038/s41598-018-22788-7

Abstract

While saline soils account for 6.5% of the total land area globally, it comprises about 70% of the area in northwestern China. Microbiota in these saline soils are particularly important because they are critical to maintaining ecosystem services. However, little is known about the microbial diversity and community composition in saline soils. To investigate the distribution patterns and edaphic determinants of bacterial communities in saline soils, we collected soil samples across the hypersaline Ebinur Lake shoreline in northwestern China and assessed soil bacterial communities using bar-coded pyrosequencing. Bacterial communities were diverse, and the dominant phyla (>5% of all sequences) across all soil samples were Gammaproteobacteria, Actinobacteria, Firmicutes, Alphaproteobacteria, Bacteroidetes and Betaproteobacteria. These dominant phyla made a significant (P < 0.05) contribution to community structure variations between soils. Halomonas, Smithella, Pseudomonas and Comamonas were the indicator taxa across the salinity gradient. Bacterial community composition showed significant (P < 0.05) correlations with salt content and soil pH. Indeed, bacterial phylotype richness and phylogenetic diversity were also higher in soils with middle-level salt rates, and were significantly (P < 0.05) correlated with salt content and soil pH. Overall, our results show that both salinity and pH are the determinants of bacterial communities in saline soils in northwest China.

Highlights

Over 800 million hectares of land throughout the world are affected by salt[1]
This study showed that bacterial communities in the saline soils under halophytic vegetation around Ebinur Lake are distinct and considerably different from those described in hypersaline sediments
Previous work found low G + C Gram-positive bacteria, Alphaproteobacteria or Deltaproteobacteria was the predominant group in many saline sediments[4,21,23,24], but Gammaproteobacteria was the dominant phylum in the saline soils in the current study

Summary

Introduction

Over 800 million hectares of land throughout the world are affected by salt[1]. Taking China as an example, northwestern China accounts for 71% of the total area of China, with 70% of the area in northwestern China comprising saline soil[2]. In the past few years, reports are available on soil microbial diversity and composition from various terrestrial habitats, yielding useful insights and highlighting the importance of contemporary soil factors such as soil moisture[10], soil trophic status[11,12,13] and soil pH14–18 Most of these studies focused on the microbiology of non-saline ecosystems. The Ebinur Lake region located in the center of an oasis, is the most representative saline ecosystem in the arid zone of China This region has a vast area of dry lakebeds covered with halophytic vegetation that plays a key role in maintaining the regional ecological balance. We hypothesized that salinity rather than other soil properties is more important in shaping bacterial community structure in the saline soil under halophytic vegetation

Methods

Results

Conclusion