Characterization of a marine gammaproteobacterium capable of aerobic anoxygenic photosynthesis
Characterization of a marine gammaproteobacterium capable of aerobic anoxygenic photosynthesis
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DOI：
10.1073/pnas.0608046104
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发表时间：
2007-02-20
影响因子：
11.1
通讯作者：
Amann, Rudolf
中科院分区：
文献类型：
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作者：
Fuchs, Bernhard M.;Spring, Stefan;Amann, Rudolf
在夏季，伽马变形菌分支NORS/OM60的成员通常构成了沿海系统浮游细菌群落的丰富部分，高达11%。在这里，我们报告了一个培养的代表，从北海地表水分离的litoralis聚集杆菌菌株KT71的几乎完整的基因组序列。出乎意料的是，发现了一个完整的光合作用超级操纵子，包括辅助色素的基因。它与来自Monterey Bay的BAC克隆具有很高的序列相似性[Beja O， Suzuki MT, Heidelberg JF, Nelson WC, Preston CM, et . (2002) Nature 415:630-633]，它们也具有几乎相同的基因排列。虽然KT71的培养物没有明显的色素沉着，但在细胞提取物中可以检测到细菌叶绿素a和螺旋黄素样类胡萝卜素。两个潜在的BLUF（使用黄素腺嘌呤二核颗粒传感器的蓝光）的存在，其中一个在基因组中的光合作用操纵子附近被发现，表明基因表达的光和氧化还原依赖调控。与其他有氧无氧光养生物（AAnPs）一样，KT71既不能厌氧生长，也不能光自养生长。培养实验和基因组证据表明，KT71需要有机底物，如羧酸、寡肽或脂肪酸来生长。菌株在微氧条件下生长最佳，并主动将自身置于接近10%氧饱和度的区域。通过对C. litoralis菌株KT71的基因组分析，确定了基于BAC序列推测的γ -变形菌海洋AAnPs为NOR5/OM60门的成员。KT71使未来的实验能够研究这组γ -变形菌AAnPs在沿海环境中的重要性。
Members of the gammaproteobacterial clade NORS/OM60 regularly form an abundant part, up to 11%, of the bacterioplankton community in coastal systems during the summer months. Here, we report the nearly complete genome sequence of one cultured representative, Congregibacter litoralis strain KT71, isolated from North Sea surface water. Unexpectedly, a complete photosynthesis superoperon, including genes for accessory pigments, was discovered. It has a high sequence similarity to BAC clones from Monterey Bay [Beja O, Suzuki MT, Heidelberg JF, Nelson WC, Preston CM, et al. (2002) Nature 415:630-633], which also share a nearly identical gene arrangement. Although cultures of KT71 show no obvious pigmentation, bacteriochlorophyll a and spirilloxanthin-like carotenoids could be detected by HPLC analysis in cell extracts. The presence of two potential BLUF (blue light using flavin adenine dinucleoticle sensors), one of which was found adjacent to the photosynthesis operon in the genome, indicates a light- and redox-dependent regulation of gene expression. Like other aerobic anoxygenic phototrophs (AAnPs), KT71 is able to grow neither anaerobically nor photoautotrophically. Cultivation experiments and genomic evidence show that KT71 needs organic substrates like carboxylic acids, oligopeptides, or fatty acids for growth. The strain grows optimally under microaerobic conditions and actively places itself in a zone of approximate to 10% oxygen saturation. The genome analysis of C. litoralis strain KT71 identifies the gammaproteobacterial marine AAnPs, postulated based on BAC sequences, as members of the NOR5/OM60 clacle. KT71 enables future experiments investigating the importance of this group of gamma-proteobacterial AAnPs in coastal environments.