Low intraspecific diversity in a Polynucleobacter subcluster population numerically dominating bacterioplankton of a freshwater pond
Low intraspecific diversity in a Polynucleobacter subcluster population numerically dominating bacterioplankton of a freshwater pond
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DOI：
10.1128/aem.71.8.4539-4547.2005
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发表时间：
2005-08-01
影响因子：
4.4
通讯作者：
Wu, QLL
中科院分区：
文献类型：
--
作者：
Hahn, MW;Pöckl, M;Wu, QLL
培养依赖和独立的方法相结合，调查的微多样性的多核菌亚群人口（β-变形菌）在数字上占主导地位的浮游细菌的一个小的，腐殖淡水池塘。完全覆盖的人口培养允许超出核糖体标记的系统发育分辨率的微多样性分析。荧光原位杂交与两个探针特异性的窄亚群C（PnecC细菌）的多核菌集群显示，这个人口贡献了60%的浮游细菌细胞总数。微多样性进行了调查的日期，在该日期观察到的PnecC的最高相对数量。构建了细菌通用引物扩增的核糖体操纵子片段（16 S rRNA基因、完整的16 S-23 S内转录间隔区1 [ITS 1]、部分23 S rRNA基因）的克隆文库。逐步筛选文库中来自PnecC细菌的片段和PnecC细菌的不同ITS基因型。通过16 S rRNA基因和ITS 1的测序对分离的PnecC菌株进行表征。克隆文库和已建立的培养物收集库都只含有相同的三种ITS基因型，其中一种基因型占克隆总数的46%。用几种方法对分离物进行基因组指纹图谱分析，结果都是每个ITS基因型只能检测到一个指纹。我们的结论是一个多核浮游细菌种群具有极低的种内多样性和不均匀的结构在数量上占主导地位的浮游细菌群落在调查的栖息地。这种低的种内多样性与海洋细菌种群中发现的高种内多样性形成强烈对比。
Cultivation-dependent and -independent methods were combined to investigate the microdiversity of a Polynucleobacter subcluster population (Betaproteobacteria) numerically dominating the bacterioplankton of a small, humic freshwater pond. Complete coverage of the population by cultivation allowed the analysis of microdiversity beyond the phylogenetic resolution of ribosomal markers. Fluorescent in situ hybridization with two probes specific for the narrow subcluster C (PnecC bacteria) of the Polynucleobacter cluster revealed that this population contributed up to 60% to the total number of bacterioplankton cells. Microdiversity was investigated for a date at which the highest relative numbers of PnecC were observed. A clone library of fragments of the ribosomal operon (16S rRNA genes, complete 16S-23S internal transcribed spacer 1 [ITS1], partial 23S rRNA genes) amplified with universal bacterial primers was constructed. The library was stepwise screened for fragments from PnecC bacteria and for different ITS genotypes of PnecC bacteria. The isolated PnecC strains were characterized by sequencing of the 16S rRNA genes and the ITS1. Both the clone library and the established culture collection contained only the same three ITS genotypes, and one of them contributed 46% to the entire number of clones. Genomic fingerprinting of the isolates with several methods always resulted in the detection of only one fingerprint per ITS genotype. We conclude that a Polynucleobacter population with an extremely low intraspecific diversity and an uneven structure numerically dominated the bacterioplankton community in the investigated habitat. This low intraspecific diversity is in strong contrast to the high intraspecific diversities found in marine bacterial populations.