Guan Yue, Ngugi David K, Vinu Manikandan, Blom Jochen, Alam Intikhab, Guillot Sylvain, Ferry James G, Stingl Ulrich
Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Bioinformatik und Systembiologie, Justus-Liebig-Universität Giessen, Giessen, Germany.
Front Microbiol. 2019 Apr 24;10:839. doi: 10.3389/fmicb.2019.00839. eCollection 2019.
Halophilic methanogens play an important role in the carbon cycle in hypersaline environments, but are under-represented in culture collections. In this study, we describe a novel strain that was isolated from the sulfide-rich brine-seawater interface of Kebrit Deep in the Red Sea. Based on physiological and phylogenomic features, strain RSK, which is the first methanogenic archaeon to be isolated from a deep hypersaline anoxic brine lake of the Red Sea, represents a novel species of this genus. In order to compare the genetic traits underpinning the adaptations of this genus in diverse hypersaline environments, we sequenced the genome of strain RSK and compared it with genomes of previously isolated and well characterized species in this genus (, , , and ). These analyses revealed a highly conserved genomic core of greater than 93% of annotated genes (1490 genes) containing pathways for methylotrophic methanogenesis, osmoprotection through salt-out strategy, and oxidative stress response, among others. Despite the high degree of genomic conservation, species-specific differences in sulfur and glycogen metabolisms, viral resistance, amino acid, and peptide uptake machineries were also evident. Thus, while species are found in diverse extreme environments, each genotype also possesses adaptive traits that are likely relevant in their respective hypersaline habitats.
嗜盐产甲烷菌在高盐环境的碳循环中发挥着重要作用，但在菌种保藏中心中所占比例较低。在本研究中，我们描述了一种从红海凯布里特海渊富含硫化物的卤水-海水界面分离出的新菌株。基于生理和系统基因组学特征，菌株RSK是首个从红海深层高盐缺氧卤水湖分离出的产甲烷古菌，代表了该属的一个新物种。为了比较该属在不同高盐环境中适应性的遗传特征，我们对菌株RSK的基因组进行了测序，并将其与该属之前分离并充分表征的物种（、、、和）的基因组进行了比较。这些分析揭示了一个高度保守的基因组核心，其中超过93%的注释基因（1490个基因）包含甲基营养型产甲烷、通过盐析策略进行渗透保护以及氧化应激反应等途径。尽管基因组保守程度很高，但在硫和糖原代谢、病毒抗性、氨基酸和肽摄取机制方面的物种特异性差异也很明显。因此，虽然该属物种存在于不同的极端环境中，但每个基因型也都具有可能与其各自的高盐栖息地相关的适应性特征。
