Halobaculum rubrum sp. nov., an extremely halophilic archaeon isolated from a salt lake

A halophilic archaeal strain, designated C46(T), was isolated from an inland salt lake in Qinghai Province, PR China. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C46(T) belongs to the genus Halobaculum, and the closest phylogenetic relative is Halobaculum gomorrense DSM 9297(T) with 97.7% similarity. Despite this, strain C46(T) was more related to Halobaculum saliterrae WSA2(T) than other members of the genus Halobaculum based on genome comparison and analysis, and the average nucleotide identity, in silico DNA-DNA hybridization, amino acid identity and percentage of conserved protein values between the two strains were 89.1, 53.3, 89.2 and 75.6%, respectively, which are lower than the cutoff values proposed for species delimitation. The physiological, biochemical, genetic and genomic characteristics of strain C46(T) were different from those of its closest phylogenetic neighbours, which indicated that this strain represents a novel species of the genus Halobacuturn, for which the name Halobaculum rubrum sp nov is proposed The type strain is C46(T) (=CGMCC 1.13737(T)=JCM 32959(T)).