基于高通量测序的乐安江冬季细菌群落特征分析

Characteristics of bacterial community in Le'an River in winter based on high-throughput sequencing

摘要:

[目的]分析乐安江从上游至下游水体细菌群落结构组成变化，揭示细菌群落结构组成变化的影响因素。[方法]分析不同河段水体中C、N、P、Cu、Zn、As和Pb等化学指标。对水体DNA的16S rRNA基因进行高通量测序确定细菌群落特征。基于Bray-Curtis距离的采样点非度量多维尺度（NMDS）分析和聚类分析研究乐安江水体细菌群落结构差异，基于冗余分析（RDA）研究环境因子与细菌群落的关系。[结果]乐安江水体中C、N、P、Cu、Zn、As和Pb等化学指标含量中下游偏高。中游河水受德兴铜矿废水影响，细菌群落多样性降低，下游受农业、生活废水影响，细菌群落丰富度和多样性升高。水体中优势菌群为β-变形菌纲（Beta-proteobacteria，53.03%）、放线菌门（Actinobacteria，20.24%）和拟杆菌门（Bacteroidetes，14.75%）。中游受德兴铜矿废水影响，Beta-proteobacteria丰度增大，而Actinobacteria丰度减小；下游受微生物间捕食影响，Bacteroidetes丰度下降。在细菌群落与环境因子的关系中，DO是解释乐安江细菌群落结构变化的最佳环境因子。[结论]乐安江中游德兴铜矿废水和中下游农业、生活废水明显改变了水体细菌群落结构组成，使水体细菌群落特征从上游到下游发生显著变化。本研究为揭示人类活动对乐安江水生态环境的影响提供了参考性数据。

Abstract:

[Objective] The aims of this study were to analyze the compositional changes of bacterial community in Le'an River from upstream to downstream, and to reveal the main environmental factors shaping the bacterial community. [Methods] The hydrochemical indicators in different reaches, such as C, N, P, Cu, Zn, As and Pb, were measured. High-throughput sequencing of 16S rRNA gene was used to profile the bacterial community structure. Non-metric Multidimensional Scale (NMDS) Analysis and Cluster Analysis of sampling sites based on Bray-Curtis distance were used to explore the bacterial community structure along Le'an River. Redundancy analyzed (RDA) was used to analyze the relationship between environmental factors and bacterial communities. [Results] The concentrations of C, N, P, Cu, Zn, As and Pb were higher in the middle and lower reaches than those in the upper reaches. The diversity of bacterial communities decreased in the middle reaches because of the wastewater from the Dexing Copper Mine, and the richness and diversity increased in the lower reaches because of the wastewater from the agricultural and domestic wastewater. The predominant bacteria composition was Beta-proteobacteria (53.03%), Actinobacteria (20.24%) and Bacteroidetes (14.75%). Due to the influence of Dexing Copper Mine, the abundance of Beta-proteobacteria increased in the middle reaches, while the abundance of Actinobacteria decreased. In the lower reaches, the abundance of Bacteroidetes decreased due to the inter-microbial predation. In the relationship between the bacterial community and environmental factors, dissolved oxygen (DO) was the best environmental factor explaining the changes of bacterial community structure along the Le'an River. [Conclusion] Wastewater from the Dexing Copper Mine in the middle reaches of Le'an River and the agricultural and domestic wastewater in the middle and lower reaches changed the bacterial community structure, resulting the significant changes of the bacterial community along Le'an River. These findings provide a reference for revealing the influences of human activities on the water ecology of the Le'an River.