School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, People's Republic of China.
School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, People's Republic of China.
Syst Appl Microbiol. 2022 May;45(3):126308. doi: 10.1016/j.syapm.2022.126308. Epub 2022 Mar 2.
The genera Halosiccatus and Halomicrobium are the most closely related genera within the family Haloarculaceae (class Halobacteria). All species of these two genera are closely related to each other in phylogenetic analyses based on their 16S rRNA gene sequences, and also using the sequences of four housekeeping genes. The genus Halosiccatus was proposed based on inferred phylogeny using only one of the three distinct 16S rRNA genes detected in strain DC8, while Halomicrobium zhouii, one of three species of Halomicrobium, was omitted from the reference species used in these analyses. The related 16S rRNA gene sequence similarities of type strains of Halomicrobium katesii and Halomicrobium mukohataei were as high as 99.5%-99.7%, much higher than the threshold values proposed as species boundaries. These issues could have resulted in taxonomic inaccuracies in the genera Halosiccatus and Halomicrobium, and a thorough study was undertaken to clarify the status of all species in both genera. Based on phylogenetic and phylogenomic analyses, the current four species of the two genera form a single clade with high bootstrap confidence, indicating that the genus Halosiccatus should be merged with Halomicrobium. Halomicrobium katesii Kharroub et al. 2008 is proposed as a later heterotypic synonym of Halomicrobium mukohataei (Ihara et al. 1997) Oren et al. 2002. An additional species is also described (strains LT50 and TH30), and was isolated from different Gobi saline soil samples of Tarim Basin, Xinjiang, China. Phenotypic, chemotaxonomic, genomic and phylogenetic properties indicated that strains LT50 (=CGMCC 1.15187 = JCM 30837) and TH30 (=CGMCC 1.15189 = JCM 30839) represent a novel species of the genus Halomicrobium, for which the name Halomicrobium salinisoli sp. nov. is proposed.
属 Halosiccatus 和 Halomicrobium 是 Haloarculaceae 科（Class Halobacteria）中最密切相关的属。基于 16S rRNA 基因序列的系统发育分析以及四个看家基因的序列，这两个属的所有种都彼此密切相关。属 Halosiccatus 是基于仅从菌株 DC8 中检测到的三个不同 16S rRNA 基因之一推断出的系统发育而提出的，而在这些分析中使用的参考种属中省略了 Halomicrobium zhouii，这是 Halomicrobium 的三个种之一。Halomicrobium katesii 和 Halomicrobium mukohataei 的模式菌株的相关 16S rRNA 基因序列相似性高达 99.5%-99.7%，远高于作为种属界限提出的阈值。这些问题可能导致 Halosiccatus 和 Halomicrobium 属的分类学不准确，因此进行了一项彻底的研究，以澄清两个属中所有种的地位。基于系统发育和系统基因组学分析，目前这两个属的四个种形成了一个具有高自举置信度的单一分支，表明属 Halosiccatus 应与 Halomicrobium 合并。 Halomicrobium katesii Kharroub 等人 2008 被提议为 Halomicrobium mukohataei (Ihara 等人 1997) Oren 等人 2002 的后期异型同义词。还描述了另一个种（LT50 和 TH30 菌株），它是从中国新疆塔里木盆地不同的戈壁盐水土壤样本中分离出来的。表型、化学分类、基因组和系统发育特性表明，LT50（=CGMCC 1.15187=JCM 30837）和 TH30（=CGMCC 1.15189=JCM 30839）菌株代表 Halomicrobium 属的一个新种，该新种命名为 Halomicrobium salinisoli sp. nov.。
