大庆湿地噬藻体和蓝藻的遗传多样性及其与环境因子的关系

Cyanophage was a kind of virus infecting cyanobacterium and distributed extensively. The research on cyanophages was a hot spot due to its playing a significant role in regulating the abundance of cyanobacterial plankton, community structure and in biogeochemical cycle. In the project, the genetic diversity and distribution of cyanophages and cyanobacteria in the natural and constructed wetlands in Daqing were investigated and the temporal change of diversity of cyanophages and cyanobacteria in the Daqing wetlands were also done with the molecular biological methods of PCR-DGGE and clonging combined with traditional isolation and purification; the PCA and CCA were applied to analysis the relationship among the environmental factors, diversity of cyanophages and cyanobacteria.Through this study, the community composition, phylogeny and distribution characteristics of cyanophages and cyanobacteria in Daqing wetlands will be clarified and the effect of environmental factors on diversity of cyanophages and cyanobacteria in Daqing wetlands will be dicovered. It provide important information for investigating the relationship between cyanophages and cyanobacteria, exposing the community structure and function of cyanophage in wetland ecosystem and developing the microbial resource to control water bloom.

噬藻体是一类分布极为广泛且能感染蓝藻的病毒，在调节浮游生物的丰度、群落结构以及生物地球化学循环中具有重要作用，而成为目前微生物学领域的一大研究热点。本项目拟以大庆天然湿地和人工湿地中噬藻体和蓝藻为研究对象，利用分离培养、PCR-DGGE及克隆技术，对噬藻体和蓝藻的遗传多样性及其分布特征进行研究；对噬藻体和蓝藻多样性在时间上的变化规律进行研究；应用PCA和CCA方法分析湿地环境因子与噬藻体和蓝藻多样性的关系。以此来阐明大庆湿地噬藻体和蓝藻的群落结构组成、系统发生及分布特征，揭示环境因子对噬藻体和蓝藻多样性的影响，为研究噬藻体与蓝藻间相互关系、明晰噬藻体在湿地生态系统中的结构与功能、开发治理水华的微生物资源提供重要的基础资料。

蓝藻及侵染蓝藻的细菌病毒（噬藻体）的多样性是当今的研究热点，大庆湿地类型丰富，噬藻体和蓝藻的多样性研究未见报道。本项目采用PCR-克隆-测序技术，调查大庆湿地水体噬藻体基因多样性和蓝藻遗传多样性；采用传统分离方法对大庆湿地水体蓝藻和噬藻体进行了分离纯化；测定了大庆湿地环境因子，分析其与噬藻体和蓝藻遗传多样性的关系。结果发现，大庆湿地水体中肌尾噬藻体g20基因类群丰富，并存在着大庆湿地特有的噬藻体类群（Wetland I~V）；大庆湿地水体中蓝藻遗传多样性丰富，龙凤湿地和扎龙湿地水体蓝藻优势类群不同，且随时间存在着不同的演替；分离并鉴定大庆湿地水样中蓝藻菌株，发现新的丝状蓝藻菌株，同源性与聚球藻（Synechococcus elongatus PCC 6301）最大（91%），分离获得了12株侵染Anabaena PCC7120的噬藻体，经电镜观察发现获得的噬藻体病毒株均为短尾病毒；采用双层平板分离和PCR-克隆-测序法明确了大庆湿地可培养噬藻体g20基因的进化地位，隶属于可培养聚球藻噬藻体类群（Cluster δ）中；大庆湿地测定的环境因子中，温度、亚硝酸和硝酸盐浓度及水体pH值是影响大庆湿地水体蓝藻群落结构的主要环境因子，其中pH值也影响着大庆湿地水体中噬藻体的群落结构。本项目的研究结果为研究噬藻体与蓝藻的相互关系提供了数据支撑和研究材料，为进一步研究大庆湿地噬藻体分布特征、大庆湿地噬藻体和蓝藻对应关系明确方向和奠定了基础。