AUTHOR=Sun Ya-Ping , Wang Bei-Bei , Wu Zhang-Ping , Zheng Xi-Wen , Hou Jing , Cui Heng-Lin 

TITLE=Halorarius litoreus gen. nov., sp. nov., Halorarius halobius sp. nov., Haloglomus halophilum sp. nov., Haloglomus salinum sp. nov., and Natronomonas marina sp. nov., extremely halophilic archaea isolated from tidal flat and marine solar salt

JOURNAL=Frontiers in Marine Science

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1105929

DOI=10.3389/fmars.2023.1105929

ISSN=2296-7745

ABSTRACT=<p>Five novel halophilic archaeal strains, named BND22<sup>T</sup>, ZY10<sup>T</sup>, ZY41<sup>T</sup>, ZY58<sup>T</sup>, and ZY43<sup>T</sup>, were isolated from the coastal saline sediment of the intertidal zone located in Qingdao and the natural sea salt produced from Huanghua marine solar saltern, PRChina. These five strains demonstrated the typical morphology and growth characteristics of haloarchaea. The comparison of 16S rRNA gene revealed that strain BDN22<sup>T</sup> was associated with <italic>Salinirubellus salinus</italic> ZS-35-S2<sup>T</sup> (95.2% similarity), strain ZY10<sup>T</sup> was related to <italic>Halosegnis rubeus</italic> F17-44<sup>T</sup> (95.1% similarity), both strains ZY41<sup>T</sup> and ZY58<sup>T</sup> were closely related to <italic>Haloglomus irregulare</italic> F16-60<sup>T</sup> (98.1% and 98.2% similarities, respectively), and strain ZY43<sup>T</sup> was close to <italic>Natronomonas salina</italic> YPL13<sup>T</sup> (98.0% similarity). In addition to the 16S rRNA gene, the <italic>rpoB′</italic> gene is undoubtedly another important molecular marker for the identification of halophilic archaea, and concatenated-conserved-protein phylogeny was widely used in archaeal classification in recent years. Phylogenetic and phylogenomic analyses based on <italic>rpoB′</italic> genes and 122 concatenated archaeal protein genes showed that these haloarchaea construct three different clades and gathered together with the current members of <italic>Haloarculaceae</italic>. Strains BND22<sup>T</sup> and ZY10<sup>T</sup> formed two distinct clades separated from <italic>Salinirubellus salinus</italic> ZS-35-S2<sup>T</sup> and <italic>Halosegnis</italic> members, strains ZY41<sup>T</sup> and ZY58<sup>T</sup> clustered with <italic>Haloglomus irregulare</italic> F16-60<sup>T</sup>, and strain ZY43<sup>T</sup> gathered with the current members of <italic>Natronomonas.</italic> The ANI, DDH, and AAI values of these five strains against phylogenetic neighbours were no more than 91%, 45%, and 92%, respectively, far below the cut-off values for species delineation, supporting their placements in new taxa. Based on the phenotypic, chemotaxonomic, phylogenetic, and phylogenomic properties, these five strains represent five novel taxa of the family <italic>Haloarculaceae</italic>, <italic>Halorarius litoreus</italic> gen. nov., sp. nov. (type strain BND22<sup>T</sup> = CGMCC 1.18780<sup>T</sup> = JCM 34966<sup>T</sup>), <italic>Halorarius halobius</italic> sp. nov. (type strain ZY10<sup>T</sup> = CGMCC 1.17475<sup>T</sup> = JCM 34319<sup>T</sup>), <italic>Haloglomus halophilum</italic> sp. nov. (type strain ZY41<sup>T</sup> = CGMCC 1.17030<sup>T</sup> = JCM 34161<sup>T</sup>), <italic>Haloglomus salinum</italic> sp. nov. (type strain ZY58<sup>T</sup> = CGMCC 1.17216<sup>T</sup> = JCM 34163<sup>T</sup>), and <italic>Natronomonas marina</italic> sp. nov. (type strain ZY43<sup>T</sup> = CGMCC 1.17202<sup>T</sup> = JCM 34162<sup>T</sup>). This is the first report of description of a novel haloarchaeon isolated from a marine intertidal zone.</p>