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^T, 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 Mg²⁺ (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^T with a sequence identity of 96.0%. Strain MBLA0158^T 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^T is distinct from previously reported type strains of the genus Halobellus. Pan-genome analysis showed that strain MBLA0158^T contains 419 genes that are not present in other type strains of the genus Halobellus. Based on overall analyses, strain MBLA0158^T 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^T (= KCTC 4318^T = JCM 36642^T).