16S rRNA genes reveal stratified open ocean bacterioplankton populations related to the Green Non-Sulfur bacteria
16S rRNA genes reveal stratified open ocean bacterioplankton populations related to the Green Non-Sulfur bacteria
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DOI：
10.1073/pnas.93.15.7979
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发表时间：
1996-07-23
影响因子：
11.1
通讯作者：
Adair, NL
中科院分区：
文献类型：
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作者：
Giovannoni, SJ;Rappe, MS;Adair, NL
微生物在海洋表层的生物地球化学中发挥着重要作用，但特定浮游细菌物种分布的时空结构在很大程度上尚未被探索，除了那些可以通过自发荧光或培养方法检测到的生物体之外。使用 rRNA 基因作为遗传标记提供了一种工具，通过该工具可以研究丰富的浮游细菌物种的生长、分布和活性模式，无论它们培养的难易程度如何。在这里，我们报告了从 1991 年 8 月在马尾藻海 250 m 处收集的海水中克隆出的一个不寻常的相关 16S rRNA 基因簇（SAR202、SAR263、SAR279、SAR287、SAR293、SAR307），当时水柱高度分层，深部叶绿素最大值位于 120 m 深度。系统发育分析和异常的 15 bp 删除证实这些基因与细菌领域的绿色非硫门有关。这是该门的代表出现在公海的第一个证据。使用寡核苷酸探针检查SAR202基因簇在大西洋和太平洋垂直剖面（0-250 m）中的分布，以及在西马尾藻海连续30个月的离散（每月）时间序列（0和200 m）中的分布。这些数据为以下结论提供了强有力的统计支持：SAR202 基因簇在深部叶绿素最大值的下边界处比例最丰富 (P = 2.33 x 10(-5))。这些结果表明，以前未曾预料到的微生物种群分层可能是海洋表层生态的一个重要因素。
Microorganisms play an important role in the biogeochemistry of the ocean surface layer, but spatial and temporal structures in the distributions of specific bacterioplankton species are largely unexplored, with the exceptions of those organisms that can be detected by either autofluorescence or culture methods. The use of rRNA genes as genetic markers provides a tool by which patterns in the growth, distribution, and activity of abundant bacterioplankton species can be studied regardless of the ease with which they can be cultured. Here we report an unusual cluster of related 16S rRNA genes (SAR202, SAR263, SAR279, SAR287, SAR293, SAR307) cloned from seawater collected at 250 m in the Sargasso Sea in August 1991, when the water column was highly stratified and the deep chlorophyll maximum was located at a depth of 120 m. Phylogenetic analysis and an unusual 15-bp deletion confirmed that the genes were related to the Green Non-Sulfur phylum of the domain Bacteria. This is the first evidence that representatives of this phylum occur in the open ocean. Oligonucleotide probes were used to examine the distribution of the SAR202 gene cluster in vertical profiles (0-250 m) from the Atlantic and Pacific Oceans, and in discrete (monthly) time series (0 and 200 m) over 30 consecutive months in the Western Sargasso Sea. The data provide robust statistical support for the conclusion that the SAR202 gene cluster is proportionately most abundant at the lower boundary of the deep chlorophyll maximum (P = 2.33 x 10(-5)). These results suggest that previously unsuspected stratification of microbial populations may be a significant factor in the ecology of the ocean surface layer.