The correlation analyses between bacterial community and the crucial environmental factors in saline-alkali soil of Songnen Plain

Abstract:

[Background] The bacteria inhabiting the saline-alkali soil of Songnen Plain have the ability to tolerate double stresses of hyper-saline/alkali environment. [Objective] Analyzing the correlation between bacterial community and the environmental factors in saline-alkali soil of Songnen Plain will offer insights into the role of uncultured bacteria in the biogeochemical cycle and support the targeted culture of functional isolates. [Methods] A total of 21 saline-alkali soil samples were collected from Daqing (Heilongjiang), Songyuan (Jilin) and Baicheng (Jilin). Illumina MiSeq platform was employed to sequence the V4 hypervariable region of bacterial 16S rRNA gene, and the obtained data were analyzed via bioinformatics tools. [Results] The saline-alkali soils of Songnen Plain were of soda (Na₂CO₃ and NaHCO₃), which mainly contained Na⁺, K⁺ and HCO₃⁻ and had pH 8.47–10.40. The bacterial diversity of DC11 sampled in Saertu district of Daqing was the highest, while that of DC2 collected in Zhaozhou was the lowest. The bacteria in the 21 samples were classified into 845 genera, 423 families of 26 phyla. The dominant phyla (97.8%) wereActinobacteria (47.3%), Proteobacteria (30.3%), Chloroflexi(7.5%), Gemmatimonadetes (7.0%), Bacteroidetes (2.5%), Firmicutes (1.7%) and Acidobacteria (1.5%). At the family level, the 21 samples were clustered into 3 groups through heatmap and principal component analysis. The redundancy analysis indicated that the content of total salt, Na⁺ and HCO₃⁻ as well as pH significantly affected the bacterial community in saline-alkali soil. [Conclusion] This study indicates that the saline-alkali soil of Songnen Plain harbors diverse bacteria, which can guide the development and utilization of the saline/alkali-tolerant bacteria and their genes.