Actinobacterial 16S rRNA genes from freshwater habitats cluster in four distinct lineages
Actinobacterial 16S rRNA genes from freshwater habitats cluster in four distinct lineages
复制标题
DOI：
10.1111/j.1462-2920.2004.00561.x
复制
发表时间：
2004-03-01
影响因子：
5.1
通讯作者：
Pernthaler, J
中科院分区：
文献类型：
--
作者：
Warnecke, F;Amann, R;Pernthaler, J
我们分析了隶属于放线菌纲的淡水细菌的16S rRNA基因的系统发育相关性。一种聚合酶链反应测定法被开发用于可靠地鉴定16S rRNA基因克隆文库内的罕见放线菌相关插入片段。在7个淡水系统构建的18个文库中，从超过1800个克隆中共收集到63个放线菌序列类型。六十个新获得的序列分组在四个不同的系统发育谱系。它们构成了目前可用的这些簇内几乎完整的序列的约75%。与来自不同土壤栖息地的>300个序列的比较显示，这些单系放线菌分支中的两个分支（acI和acII）几乎完全具有来自淡水和河口的16S rRNA序列类型。这可能表明，这些细菌不是从陆地来源接种到淡水中，而是淡水微生物组合的本地成分。与此相反，从淡水，海洋沉积物和土壤的序列类型明显混合在另一个放线菌谱系（acIV）。序列分歧acIV是最高的所有四个谱系（88%的最低相似性），这可能反映了它的辐射在几个栖息地类型。在淡水谱系内，从地理上遥远的水生系统中检索到基本相同的序列类型的组，具有显著不同的水文和湖沼特征。这表明，有必要调查基因型的变异，在原位丰度和活动，这些放线菌在淡水浮游生物更详细的培养独立的技术。
We analysed the phylogenetic relatedness of 16S rRNA genes from freshwater bacteria affiliated with the class Actinobacteria. A polymerase chain reaction assay was developed to identify reliably rare Actinobacteria-related inserts within 16S rRNA gene clone libraries. In 18 libraries constructed from seven freshwater systems, altogether 63 actinobacterial sequence types were collected from a total of >1800 clones. Sixty of the newly obtained sequences grouped within four distinct phylogenetic lineages. They constitute approximately 75% of the nearly complete sequences within these clusters that are presently available. A comparison with >300 sequences from various soil habitats revealed that two of these monophyletic actinobacterial clades (acI and acII) almost exclusively harbour 16S rRNA sequence types from freshwaters and estuaries. This may indicate that such bacteria are not inoculated to freshwaters from terrestrial sources, but are autochthonous components of freshwater microbial assemblages. In contrast, sequence types from freshwaters, marine sediments and soils were clearly mixed in another of the actinobacterial lineages (acIV). Sequence divergence within acIV was the highest of all four lineages (88% minimum similarity), which potentially reflects its radiation across several habitat types. Within the freshwater lineages, groups of essentially identical sequence types were retrieved from geographically distant aquatic systems with strikingly different hydrological and limnological characteristics. This points to the necessity to investigate genotypic variability, in situ abundances and activities of these Actinobacteria in freshwater plankton in greater detail by cultivation-independent techniques.