Halogranum salarium sp. nov., a halophilic archaeon isolated from sea salt

Three halophilic archaea, strains B-1T, B-3 and B-4, were isolated from evaporitic salt crystals from Namhae, Korea. Cells of the strains were Gram-stain-negative, motile and pleomorphic, and colonies were red-pigmented. The three isolates had identical 16S rRNA gene sequences and formed a tight phylogenetic clade with Halogranum rubrum RO2-11T in the genus Halogranum, showing 99.5% sequence similarity. The next most closely related species were Halogranum amylolyticum and Halogranum gelatinilyticum (97.4 and 96.3% similarity to the respective type strains). The phylogeny based on the full-length RNA polymerase subunit B′ gene (rpoB′) was in agreement with the 16S rRNA gene sequence analysis, but allowed better discrimination. DNA–DNA hybridization between a representative strain (B-1T) and the type strains of Hgn. rubrum, Hgn. amylolyticum and Hgn. gelatinilyticum revealed less than 40% relatedness. Polar lipid analysis showed that the three isolates contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and three glycolipids. Combined genotypic and phenotypic data supported the conclusion that strains B-1T, B-3 and B-4 represent a novel species of the genus Halogranum, for which the name Halogranum salarium sp. nov. is proposed. The type strain is B-1T (=KCTC 4066T = DSM 23171T).