基于16S rRNA基因高通量测序的乌江流域梯级水库表层沉积物微生物群落分析

Microbial Community Analysis in Surface Sediments of Wujiang Cascade Reservoirs Based on 16S rRNA High-throughput Sequencing

微生物群落在湖库沉积物生态系统的物质循环中发挥着重要作用,但对大规模梯级筑坝形成水库库区沉积物微生物的研究并不多见。本工作以乌江干流7个梯级水库为研究对象,针对微生物非常活跃的表层沉积物,基于16S rRNA基因高通量测序技术分析不同水库微生物群落多样性和组成差异及其对环境因子的响应。结果表明:乌江流域梯级水库表层沉积物中,微生物群落α多样性指数总体上呈现从上游到下游逐渐降低的趋势;β多样性表现为洪家渡水库和乌江渡水库的微生物群落与其他水库差异性较大,这可能与它们较长的库龄或滞水时间有关。变形菌门是各水库沉积物中微生物群落门水平上相对丰度最高的优势菌门(Proteobacteria,17.28%~30.40%),其中γ-变形菌纲为纲水平的优势菌(Gammaproteobacteria,12.14%~28.08%)。库龄是控制水库表层沉积物微生物群落结构特征的主要环境因子,微生物群落多样性和稳定性随着水库库龄的增大而降低,微生物群落构建过程主要受随机性过程的主导。研究结果揭示了不同库龄梯级水库微生物群落的演化机制,为水库合理开发和水资源的可持续利用提供重要科学依据。

Microbial communities play an important role in the material cycling in lake sediment ecosystems.However,there are only a few studies on sediment microbes in the reservoirs formed by large-scale cascade damming.Here,the diversity and composition of microbial communities in different reservoirs,as well as their responses to environmental factors were analyzed in the surface sediments of seven cascade reservoirs in the main stream of the Wujiang River.The results show that the α-diversity index of microbial communities generally decreased from upstream to downstream in the surface sediments of the Wujiang cascade reservoirs.The β-diversity reveals that the microbial communities of Hongjiadu and Wujiangdu Reservoir were different from the others.This may be due to their longer reservoir age and stagnation time.Proteobacteria is the dominant phylum(17.28%-30.40%)at the level of microbial community in all reservoir sediments,and Gammaproteobacteria is the major phylum at the class level(12.14%-28.08%).Reservoir age is the main environmental factor controlling the structural characteristics of microbial communities in surface sediments.The diversity and stability of microbial communities decreased with increasing reservoir age,and the construction of microbial community is mainly governed by the stochastic process.This study reveals the evolution mechanism of microbial communities in cascade reservoirs of different ages,delivering an indispensable scientific basis for the reservoir development and the sustainable use of water resources.