Unsuspected diversity among marine aerobic anoxygenic phototrophs
Unsuspected diversity among marine aerobic anoxygenic phototrophs
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DOI：
10.1038/415630a
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发表时间：
2002-02-07
期刊：
影响因子：
64.8
通讯作者：
DeLong, EF
中科院分区：
文献类型：
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作者：
Béjà, O;Suzuki, MT;DeLong, EF
含有细菌叶绿素 a (Bchla) 的需氧、缺氧、光养细菌的生长和 Bchla 合成都需要氧气(1-6)。最近的报告表明，这些细菌广泛分布在海洋浮游生物中，它们可能占海洋表面光合电子传输的 5% 7 和总微生物群落的 11% (8)。已知的浮游无氧光养生物仅属于变形菌a亚类中的少数几个受限制的群体。在这里，我们报告了天然海洋细菌中光合基因内容和操纵子组织的基因组分析。这些光合基因簇包括一些与β亚类变形菌最相似的基因簇，这些基因簇以前从未在海洋环境中观察到。此外，这些光合基因广泛分布在海洋浮游生物中，并在浅海浮游细菌组合中活跃表达，表明新鉴定的光养生物具有光合能力。我们的数据表明，浮游细菌群并不像之前提出的那样简单地由一类均匀、分布广泛的缺氧光养生物组成(8)；相反，这些组合包含多个亲缘关系较远的、具有光合作用活性的细菌群，其中包括一些与已知和栽培类型无关的细菌群。
Aerobic, anoxygenic, phototrophic bacteria containing bacteriochlorophyll a (Bchla) require oxygen for both growth and Bchla synthesis(1-6). Recent reports suggest that these bacteria are widely distributed in marine plankton, and that they may account for up to 5% of surface ocean photosynthetic electron transport 7 and 11% of the total microbial community(8). Known planktonic anoxygenic phototrophs belong to only a few restricted groups within the Proteobacteria a-subclass. Here we report genomic analyses of the photosynthetic gene content and operon organization in naturally occurring marine bacteria. These photosynthetic gene clusters included some that most closely resembled those of Proteobacteria from the beta-subclass, which have never before been observed in marine environments. Furthermore, these photosynthetic genes were broadly distributed in marine plankton, and actively expressed in neritic bacterioplankton assemblages, indicating that the newly identified phototrophs were photosynthetically competent. Our data demonstrate that planktonic bacterial assemblages are not simply composed of one uniform, widespread class of anoxygenic phototrophs, as previously proposed(8); rather, these assemblages contain multiple, distantly related, photosynthetically active bacterial groups, including some unrelated to known and cultivated types.