“Candidatus Thermonerobacter thiotrophicus,” A Non-phototrophic Member of the Bacteroidetes/Chlorobi With Dissimilatory Sulfur Metabolism in Hot Spring Mat Communities
“Candidatus Thermonerobacter thiotrophicus,” A Non-phototrophic Member of the Bacteroidetes/Chlorobi With Dissimilatory Sulfur Metabolism in Hot Spring Mat Communities
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DOI：
10.3389/fmicb.2018.03159
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
V. Thiel;Amaya M Garcia Costas;Nathaniel W. Fortney;Joval N. Martinez;M. Tank;E. Roden;E. Boyd;
中科院分区：
文献类型：
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作者：
V. Thiel;Amaya M Garcia Costas;Nathaniel W. Fortney;Joval N. Martinez;M. Tank;E. Roden;E. Boyd;
在这项研究中，我们提出了一种新的、具有异化硫代谢的嗜热菌的证据，暂时将其命名为“Candidatus Thermonerbacter thiotroicus”，它隶属于类杆菌/Ignavib/Chlorobi，我们预测它是一种硫酸盐还原细菌。异化硫酸盐还原(DSR)是一种重要的、古老的节能代谢过程，对地球化学硫和碳循环具有重要意义。特征硫酸盐还原微生物(SRM)在数量有限的细菌和古菌门中被发现。然而，基于高度多样化的环境dsrAB序列，必须存在各种未培养和未鉴定的SRM。最近高通量测序方法的发展使得对其中一些未培养的SRM进行系统发育鉴定。在这项研究中，我们鉴定了一种新的假定的SRM，它栖息在温泉微生物垫上，它是OPB56分支的成员。Kapabacteria“)属于拟杆菌属/绿细菌纲。这种新生物的部分基因组是从美国和日本黄石国家公园三个不同温泉的超基因组中提取的。Diel转录本分析支持这种生物在缺氧期间硫酸盐还原代谢的预测，表明所有DSR相关基因在夜间的原位相对转录水平最高。白天转录的末端氧化酶的存在进一步表明，这些生物也可能进行有氧呼吸。与硫氧化、氯光养绿藻的系统发育关系进一步提出了异化硫代谢进化的新问题。
In this study we present evidence for a novel, thermophilic bacterium with dissimilatory sulfur metabolism, tentatively named “Candidatus Thermonerobacter thiotrophicus,” which is affiliated with the Bacteroides/Ignavibacteria/Chlorobi and which we predict to be a sulfate reducer. Dissimilatory sulfate reduction (DSR) is an important and ancient metabolic process for energy conservation with global importance for geochemical sulfur and carbon cycling. Characterized sulfate-reducing microorganisms (SRM) are found in a limited number of bacterial and archaeal phyla. However, based on highly diverse environmental dsrAB sequences, a variety of uncultivated and unidentified SRM must exist. The recent development of high-throughput sequencing methods allows the phylogenetic identification of some of these uncultured SRM. In this study, we identified a novel putative SRM inhabiting hot spring microbial mats that is a member of the OPB56 clade (“Ca. Kapabacteria”) within the Bacteroidetes/Chlorobi superphylum. Partial genomes for this new organism were retrieved from metagenomes from three different hot springs in Yellowstone National Park, United States, and Japan. Supporting the prediction of a sulfate-reducing metabolism for this organism during period of anoxia, diel metatranscriptomic analyses indicate highest relative transcript levels in situ for all DSR-related genes at night. The presence of terminal oxidases, which are transcribed during the day, further suggests that these organisms might also perform aerobic respiration. The relative phylogenetic proximity to the sulfur-oxidizing, chlorophototrophic Chlorobi further raises new questions about the evolution of dissimilatory sulfur metabolism.