Assessment of microbial diversity in various saline soils driven by salt content

Abstract

The Yellow River Delta, as an important reserve land resource area, faces soil salinization problems. Understanding the bacterial community composition in saline soils is an important foundation for control and utilization of saline soils. However, few studies have been conducted on the composition of bacterial communities in soils with different degrees of salinization. Thus, saline soils categorized into low-salinity (LS), medium-salinity (MS), and high-salinity (HS) based on electrical conductivity (EC) were collected. The 16S rRNA high-throughput sequencing analysis was performed to analyze the effects of salinities on soil bacterial community patterns, as well as the relationships between soil bacterial communities and environmental factors. The results showed that Actinobacteriota, Proteobacteria, Chloroflexi, Firmicutes, Acidobacteriota, Gemmatimonadota and Bacteroidota accounted for almost 90 % of all the bacterial community. The linear discriminant analysis effects (LDA > 3.7) showed that 6, 5 and 3 biomarkers were present in LS, MS and HS soils, respectively, which indicated EC was an important factor influencing the saline soil bacterial community patterns. Redundancy analysis further revealed that the primary environmental parameters impacting the bacterial community were pH, EC, nitrate nitrogen, available phosphorus, total phosphorus, and soil organic matter. According to network analysis, the microbial network complexity was increased steadily with increasing of soil salinity. These findings together revealed that bacterial communities could serve as a reliable way to assess and improve the quality of salinized soils.