Scientists Uncovered Biogeographic Distribution Patterns of Bacterial Communities in Saline Agricultural Soil

Microbial communities largely determine the sustainable productivity of agroecosystems. Understanding the spatial distributions and ecological diversity of soil microbial communities in agricultural ecosystems is crucial for improvements in nutrient management and crop productivity. Research on microbial communities' distribution in saline agricultural soils is rudimentary. Especially for saline fields in arid zone, special environment factors, e.g., high salinity, low moisture and organic matter content, might shape unique microbial biogeographic patterns.

Researchers from the State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, investigated the co-occurrence and biogeographical patterns of bacterial communities in saline agricultural soils at a regional scale in north-west China. The results revealed a trend towards increasing bacterial abundance at higher longitudes. By contrast, bacterial diversity exhibited different spatial patterns and declined with increasing salinity.

Bacteroidetes, Gammaproteobacteria, Alphaproteobacteria and Gemmatimonadetes were the dominant groups across all soil samples. Additionally, members belonging to Flavobacteriaceae, Cytophagaceae, Halomonadaceae, Acidobacteria and Gemmatimonadetes were identified as indicators across the salinity gradient. Geographical distance explained 5.08% of the community variation, whereas soil parameters explained 27.26% variation, with salinity was more important than soil pH, nutrients and moisture in affecting community variation. Salinity levels also affected the modularity of bacterial co-occurrence networks, with module composition differing between soil salinity levels. Interestingly, bacterial groups belonging to Acidobacteria were the keystone taxa in saline-alkaline soils, which might be linked to their ability to decompose organic matter.

These findings offer new insights into microbial biogeography in saline agricultural soils, and improve our ability to predict how soil bacterial communities respond to environmental changes.

The research results were published in Geoderma, entitled "Biogeographical distribution of bacterial communities in saline agricultural soil".

Article link: https://www.sciencedirect.com/science/article/pii/S0016706118320883 

A) Maps of the bacterial abundance and diversity in the study area generated through kriging. B) Network analysis showing the co-occurrence in bacterial communities at various salinity levels. C) The effects of geographical distance and soil variables on the phylogenetic structure of bacterial communities 

Contact: LIU Jie, Xinjiang Institute of Ecology and Geography

E-mail: liujie@ms.xjb.ac.cn