Halorussus rarus gen. nov., sp. nov., a new member of the family Halobacteriaceae isolated from a marine solar saltern

Abstract

Two halophilic archaeal strains TBN4(T) and TBN5 were isolated from Taibei marine solar saltern in Jiangsu, China. Both strains showed light red-pigmented colonies and their cells were rod, motile and Gram-stain-negative. They were able to grow at 25-50°C (optimum 37°C), at 1.4-4.3 M NaCl (optimum 2.1 M NaCl), at 0-1.0 M MgCl(2) (optimum 0.005 M MgCl(2)) and at pH 6.0-9.0 (optimum pH 7.0). Their cells lyse in distilled water and minimal NaCl concentration to prevent cell lysis is 8% (w/v). The major polar lipids of the two strains were PG (phosphatidylglycerol), PGP-Me (phosphatidylglycerol phosphate methyl ester), PGS (phosphatidylglycerol sulfate) and five glycolipids chromatographically identical to S-TGD-1 (sulfated galactosyl mannosyl glucosyl diether), S-DGD-1 (sulfated mannosyl glucosyl diether), TGD-1 (galactosyl mannosyl glucosyl diether), DGD-1 (mannosyl glucosyl diether) and DGD-2 (an unknown diglycosyl diether). Phylogenetic analysis revealed that TBN4(T) and strain TBN5 formed a distinct clade with genus Haladaptatus (showing 90.0-90.9% 16S rRNA gene similarities). The DNA G + C content of strain TBN4(T) and strain TBN5 are 66.1 and 65.4 mol%, respectively. The DNA-DNA hybridization value between strain TBN4(T) and strain TBN5 was 94.3%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain TBN4(T) and strain TBN5 represent a novel species in a new genus within the family Halobacteriaceae, for which the name Halorussus rarus gen. nov., sp. nov. is proposed. The type strain is TBN4(T) (=CGMCC 1.10122(T) = JCM 16429(T)).