东太湖表层沉积物放线菌群落结构多样性及其空间异质性

Phylogenetic diversity and spatial heterogeneity of Actinobacteria communities in the surface sediments of the East Taihu Lake

采用基于16S rRNA基因变性梯度凝胶电泳(DGGE)方法,考察东太湖表层沉积物放线菌群落结构多样性及其空间分布特征。结果显示:东太湖表层沉积物中放线菌群落结构多样性较高,DGGE指纹图谱样品的平均条带数为21.5±2个,群落结构多样性(如Shannon-Wiener指数)在空间尺度上差异不明显;聚类分析表明放线菌群落结构空间分布特征表现为相邻采样位点群落结构较为相似,这可能与相邻位点沉积物理化性质类似有关。典型对应分析结果表明,东太湖表层沉积物中放线菌群落结构变化的主要影响因子为沉积物pH。

We used denaturing gradient gel electrophoresis （DGGE） fingerprints to examine genetic diversity and spatial distribution of actinobacterial community composition （ACC） in surface sediments of East Taihu Lake. It was shown that there was a high degree of genetic diversity, and an average of 21.5±2 bands was identified from the DGGE profiles. However, the community diversity （i.e., Shannon-Wiener index） did not show an apparent pattern among all sampling sites. And the cluster analysis indicated that the spatial variations of ACC were related to the location of sampling sites. That is, the larger distance of the sampling sites, the more dissimilarity of the ACC. This may be caused by the similar physicochemical factors between pairwise sites. Canonical correspondence analysis （CCA） was carried out to examine the relationship between environmental variables and ACC, and sediment pH was identified as the key factor in regulating the variations of ACC.