Dinitrogen fixation in a unicellular chlorophyll d-containing cyanobacterium
Dinitrogen fixation in a unicellular chlorophyll d-containing cyanobacterium
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DOI：
10.1038/ismej.2011.199
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发表时间：
2012-07-01
期刊：
影响因子：
11
通讯作者：
Hess, Wolfgang R.
中科院分区：
文献类型：
--
作者：
Pfreundt, Ulrike;Stal, Lucas J.;Hess, Wolfgang R.
Acaryo绿藻属的海洋蓝藻是唯一已知的使用叶绿素 d 作为光合色素的生物。然而，根据化学沉积物分析，叶绿素 d 已被认为广泛存在于海洋和湖泊环境中。因此，了解该属不同生理学的遗传基础和可能的生态位适应具有高度相关性。在这里，我们表明，与所有其他已知的 Acaryocholis 分离株不同，从大堡礁苍鹭岛周围水域分离出来的菌株 HICR111A 拥有一个独特的基因组区域，其中包含固氮和辅因子生物合成的结构蛋白和酶活性蛋白的所有基因。他们的系统发育分析表明与某些其他海洋蓝细菌的固氮基因有密切关系。我们证明了 Acaryoloris sp 的固氮作用。 HICR111A 以光暗依赖性方式进行调节。我们得出的结论是，固氮是细菌中已知的最复杂的生理特征之一，它可能通过水平基因转移在海洋微生物之间转移，其转移的频率可能比迄今为止预期的要高。我们的数据表明，在海洋微生物的这一分支中，产氧光合作用和固氮这两个强大的过程同时发生在同一个细胞中，并且将螨绿藻描述为生态位中一种生理上多才多艺的居民，其主要由远红光的吸收驱动。 ISME 杂志 (2012) 6, 1367-1377; doi：10.1038/ismej.2011.199； 2012 年 1 月 12 日在线发布
Marine cyanobacteria of the genus Acaryochloris are the only known organisms that use chlorophyll d as a photosynthetic pigment. However, based on chemical sediment analyses, chlorophyll d has been recognized to be widespread in oceanic and lacustrine environments. Therefore it is highly relevant to understand the genetic basis for different physiologies and possible niche adaptation in this genus. Here we show that unlike all other known isolates of Acaryochloris, the strain HICR111A, isolated from waters around Heron Island, Great Barrier Reef, possesses a unique genomic region containing all the genes for the structural and enzymatically active proteins of nitrogen fixation and cofactor biosynthesis. Their phylogenetic analysis suggests a close relation to nitrogen fixation genes from certain other marine cyanobacteria. We show that nitrogen fixation in Acaryochloris sp. HICR111A is regulated in a light-dark-dependent fashion. We conclude that nitrogen fixation, one of the most complex physiological traits known in bacteria, might be transferred among oceanic microbes by horizontal gene transfer more often than anticipated so far. Our data show that the two powerful processes of oxygenic photosynthesis and nitrogen fixation co-occur in one and the same cell also in this branch of marine microbes and characterize Acaryochloris as a physiologically versatile inhabitant of an ecological niche, which is primarily driven by the absorption of far-red light. The ISME Journal (2012) 6, 1367-1377; doi:10.1038/ismej.2011.199; published online 12 January 2012