Fine-scale phylogenetic architecture of a complex bacterial community
Fine-scale phylogenetic architecture of a complex bacterial community
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DOI：
10.1038/nature02649
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发表时间：
2004-07-29
期刊：
影响因子：
64.8
通讯作者：
Polz, MF
中科院分区：
文献类型：
--
作者：
Acinas, SG;Klepac-Ceraj, V;Polz, MF
尽管分子数据已经揭示了微生物多样性的巨大范围(1)，但即使对于定义明确的天然微生物群落，仍有两个基本问题没有答案：有多少细菌类型共存，这些类型是否自然地组织成具有潜在生态意义的系统发育离散单元？有人认为，如果没有这些信息，就无法对微生物的环境功能、种群生物学和生物地理学进行严格的探索(2)。在这里，我们通过对沿海浮游细菌群落的两个大型16S核糖体RNA克隆文库进行全面采样来解决这些问题。我们发现，对普通图书馆建设技术产生的人工制品的补偿揭示了社区组成的精细尺度模式。在样本中检测到至少516种核糖型（独特的rRNA序列），通过统计外推，在样本群体中至少有1633种共存的核糖型。超过50%的核型落在离散的簇中，序列差异小于1%。这种模式不能用互操作子的变异来解释，这表明在这个群落中有很大的近亲类群优势。我们认为，这种微多样性集群是通过选择性清除而产生的，并持续存在，因为竞争机制太弱，无法从它们内部清除多样性。
Although molecular data have revealed the vast scope of microbial diversity(1), two fundamental questions remain unanswered even for well-defined natural microbial communities: how many bacterial types co-exist, and are such types naturally organized into phylogenetically discrete units of potential ecological significance? It has been argued that without such information, the environmental function, population biology and biogeography of microorganisms cannot be rigorously explored(2). Here we address these questions by comprehensive sampling of two large 16S ribosomal RNA clone libraries from a coastal bacterioplankton community. We show that compensation for artefacts generated by common library construction techniques reveals fine-scale patterns of community composition. At least 516 ribotypes ( unique rRNA sequences) were detected in the sample and, by statistical extrapolation, at least 1,633 co-existing ribotypes in the sampled population. More than 50% of the ribotypes fall into discrete clusters containing less than 1% sequence divergence. This pattern cannot be accounted for by interoperon variation, indicating a large predominance of closely related taxa in this community. We propose that such microdiverse clusters arise by selective sweeps and persist because competitive mechanisms are too weak to purge diversity from within them.