Genome‑based classification of the family Natrialbaceae and description of four novel halophilic archaea from three saline lakes and a saline-alkaline land.

The current representatives of the family Natrialbaceae within the class Halobacteria were subjected to phylogenetic, phylogenomic, and comparative genomic analyses. The current species of Halobiforma and Halomontanus were found to be related to those of Natronobacterium and Natronoglomus, respectively. According to the cutoff value of average amino acid identity (AAI) (≤ 76%) proposed to differentiate genera within the family Natrialbaceae, Halobiforma, and Natronoglomus should be merged with Natronobacterium and Halomontanus, respectively. Beyond these, four novel halophilic archaeal strains, CCL63^T, AD-5^T, CG52^T, and KLK7^T, isolated from three saline lakes and a saline-alkaline land in China, were simultaneously subjected to polyphasic classification. The phenotypic, phylogenetic, phylogenomic, and comparative genomic analyses indicated that strain CCL63^T (= CGMCC 1.18663^T = JCM 35096^T) represents a novel genus of the family Natrialbaceae, strains AD-5^T (= CGMCC 1.13783^T = JCM 33734^T) and CG52^T (= CGMCC 1.17139^T = JCM 34160^T) represent two novel species of the genus Natronococcus, and strain KLK7^T (= MCCC 4K00128^T = KCTC 4307^T) represents a novel species of Haloterrigena. Halovalidus salilacus gen. nov., sp. nov., Natronococcus wangiae sp. nov., Natronococcus zhouii sp. nov., and Haloterrigena salinisoli sp. nov. are further proposed based on these type strains accordingly.