Genome-based classification of Halobellus rubicundus sp. nov., a novel extremely halophilic archaeon isolated from a Korean solar saltern.

A novel extremely halophilic archaeon designated, MBLA0158, was isolated from a solar saltern in Sorae, Republic of Korea. The colonies are red-pigmented, Gram-stain-negative, pleomorphic, non-motile, and lysed in distilled water. The strain grows at 25-45 °C (optimum, 37 °C), in 15-30% (w/v) NaCl (optimum, 20%) and 0.1-1.0 M Mg (optimum, 0.2-0.3 M) at pH 6.0-10.0 (optimum, 7.0-8.0). Comparative analysis based on the 16S rRNA gene sequence revealed that this strain is most closely related to the Halobellus inordinatus YC20 with a sequence identity of 96.0%. Strain MBLA0158 contained phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester as major polar lipids. The genome size is 3.29 Mb and the DNA G + C content is 66.9 mol%. Phylogenomic analysis confirmed that strain MBLA0158 is distinct from previously reported type strains of the genus Halobellus. Pan-genome analysis showed that strain MBLA0158 contains 419 genes that are not present in other type strains of the genus Halobellus. Based on overall analyses, strain MBLA0158 is considered to represent a new species of the genus Halobellus, for which the name Halobellus rubicundus sp. nov. is proposed. The type strain is MBLA0158 (= KCTC 4318 = JCM 36642).