松嫩平原盐碱土细菌群落结构及环境互馈关系

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

摘要:

【背景】松嫩平原盐碱土中孕育着能抗衡外界盐碱双重胁迫的细菌群。【目的】通过分析松嫩平原盐碱土的理化性质、细菌群落组成及其主控环境因子，为阐明未培养细菌在盐碱土的生物地球化学循环过程中的作用和定向培养功能细菌提供数据支持。【方法】以松嫩平原西部的黑龙江省大庆和吉林省的松原、白城3个地区采集的21份盐碱土样为样本，以细菌16S rRNA基因V4高变区为靶向序列，应用Illumina Miseq平台，结合生物信息学手段进行深入解析。【结果】松嫩平原盐碱土属于“苏打型(Na₂CO₃和NaHCO₃)”，主要含Na⁺和K⁺及HCO₃⁻，pH范围为8.47–10.40。黑龙江省大庆市萨尔图区DC11样本细菌的多样性最高，而黑龙江省肇州县DC2样本的多样性最低。21个样本中的细菌群被归为26个门423个科845个属。其中，以放线菌门(47.3%)、变形菌门(30.3%)、绿弯菌门(7.5%)、芽单胞菌门(7.0%)、拟杆菌门(2.5%)、厚壁菌门(1.7%)和酸杆菌门(1.5%)为主(共计97.8%)。在科水平上，通过聚类热图和主成分分析(principal component analysis，PCA)，21个样本被分为3组。冗余分析(redundancy analysis，RDA)发现总盐、Na⁺、HCO₃⁻含量和pH是影响细菌群落组成的主要环境因子。【结论】松嫩平原盐碱土中栖息繁殖多种类型的细菌群，可为微生物及其基因等资源的开发利用提供理论基础。

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.