【作者】 宋洪宁；

【导师】 丁延芹； 汪光义；

【作者基本信息】 山东农业大学 ， 微生物学， 2010， 硕士

【摘要】 本研究采用T-RFLP(末端限制性片段长度多态性)技术和构建细菌16S rDNA克隆文库等分子生物学方法调查了来自于东平湖中6个采样点的枯水期和丰水期样品的微生物群落结构,并结合相关环境数据,通过PCA(主成分分析)、RDA(冗余分析)、CCA(典型对应分析)等统计学方法分析了细菌群落结构及其与环境因子之间的关系。多样性分析结果表明,东平湖沉积物细菌群落由16个细菌类群组成,包括:变形杆菌门(Proteobacteria,包括α、β、δ、ε和γ亚门)、酸杆菌门(Acidobacteria)、浮霉菌门(Planctomycetes)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、疣微菌门(Verrucomicrobia)、硝化螺旋菌门(Nitrospira)、绿弯菌门(Chloroflexi)、芽单胞菌门(Gemmatimonadetes)、绿菌门(Chlorobi)、蓝藻门(Cyanobacteria)、脱铁杆菌门(Deferribacteres)、放线菌门(Actinobacteria)、螺旋体门(Spirochaetes)以及待划分类群OP8和OP11。来自于不同采样点和不同时期的样品间的细菌群落多样性具有明显差异。变形杆菌类群中的β-、δ-和γ-变形杆菌在11个文库(共12个)中占据优势地位。基于16S rDNA克隆文库的多样性指数分析结果表明,来自丰水期的1号点和4号点的样品具有最高的细菌多样性,而2号点样品的细菌多样性则最低。CCA和RDA分析结果都表明,沉积物中的总磷含量是与东平湖沉积物细菌群落分布相关性最强的环境因子。而对16S rDNA文库数据进行的RDA结果显示,沉积物中的浮霉菌类群与沉积物总磷含量具有最大的正相关性,适合于高磷含量的生长环境。此外,β-变形杆菌、δ-变形杆菌、ε-变形杆菌、拟杆菌以及芽单胞菌类群细菌均与总磷含量呈正相关。而酸杆菌、γ-变形杆菌、变形杆菌、厚壁菌、疣微菌、硝化螺旋菌、绿弯菌门、蓝藻门和脱铁杆菌类群则都与沉积物总磷含量呈负相关。对T-RFLP数据进行的典型对应分析结果显示,558、64.5、164、509和543 bp T-RF的分布受环境因子的影响明显,而其他14种主要的T-RFs在不同样品间分布较为平均,受环境因子的差异影响不大。实验结果表明,人为活动对东平湖沉积物环境产生极大影响,并进一步影响了其沉积物的细菌群落结构。更多还原

【Abstract】 Microbial community diversity and composition at six stations of Lake Dongping in two seasons were investigated using molecular approaches (Terminal restriction fragment length polymorphisam (T-RFLP) and 16S rDNA clone libraries). Statistical methods, such as PCA (Redundance Analysis), CCA (Canonical Correspondence Analysis), and RDA (Redundance Analysis), was used to investigate the relationship between bacterial communities of Lake Dongping sediment and environmental factors.Members of sediment bacterial communities in Lake Dongping included 16 phyla (or subphylum): Proteobacteria (includingα-Proteobacteria,β-Proteobacteria,δ-Proteobacteria,ε-Proteobacteria,γ-Proteobacteria), Acidobacteria, Planctomycetes, Bacteroidetes, Firmicutes, Verrucomicrobia, Nitrospira, Chloroflexi, Gemmatimonadetes, Chlorobi, Cyanobacteria, Deferribacteres, Actinobacteria, OP8, Spirochaetes and OP11. Bacterial diversity and composition displayed noticeable spatial and temporal variations at 6 stations. Beta-, delta-, and gamma-proteobacterial sequences were dominated in 11 of 12 clone libraries derived from sediments. The greatest bacterial diversity was present in samples collected in station 1 and station 4 in July and the least diversity in those collected in station 2 in October. The results of CCA and RDA indicated that TP (Total phosphorus) was the most important environmental factor to influence the structure of bacterial communities in sediments of Lake Dongping. Total phosphorus concentration significantly correlated to the distribution of bacterial communities in sediments of Lake Dongping. RDA was used to analysis the relationships between bacterial species and environmental factor. Planctomycetes showed the highest positive correlation with concentration of TP.β-Proteobacteria, δ-Proteobacteria,ε-Proteobacteria, Bacteroidetes, and Gemmatimonadetes were all positively correlated with TP. Additionally, Acidobacteria,γ-Proteobacteria,α-Proteobacteria, Firmicutes, Verrucomicrobia, Nitrospira, Chloroflexi, Chlorobi, Cyanobacteria, and Deferribacteres were all negatively correlated with TP. The results of CCA based on T-RFLP suggested that the abundance of 558, 64.5, 164, and 509 bp T-RFs were significant affected by environmental factors, while other 14 T-RFs were not significant correlated with environmental factors.Our results suggest that different environmental stressors contribute to spatial and temporal variations of physiochemical features and bacterial communities in sediments of Lake Dongping.更多还原