Roseovarius halophilus sp. nov., Roseovarius salis sp. nov. and Roseovarius salincola sp. nov., three novel species of the genus Roseovarius from different saline lakes

Three Gram-stain-negative, non-motile and halotolerant bacterial strains, designated as SYSU LYC5161T, SYSU LYC5162T and EGI FJ00037T, were isolated from sediment samples of different saline lakes in China. The taxonomic positions of these isolates were determined using the polyphasic taxonomic analysis. Phylogenetic analyses based on 16S rRNA gene sequences and genome comparisons revealed that these strains formed distinct clades within related type species as Roseovarius salinarum N53T, Roseovarius amoyensis GCL8T and Roseovarius halotolerans DSM 29507T from the genus Roseovarius. Based on the genome sequencing data, the G+C contents of strains SYSU LYC5161T, SYSU LYC5162T and EGI FJ00037T were 65.8 mol%, 66.1 mol% and 63.3mol%, respectively. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values of all three strains against related type species in the genus Roseovarius were below the cut-off values proposed for the delineation of a novel species. The novel isolates were distinguished from other Roseovarius species by their distinct phenotypic, physiological and genotypic characteristics. The major respiratory quinone of these strains was Q-10. The major polar lipids included diphosphatidylglycerol and phosphatidylglycerol. These results indicate that these strains represent three novel species within the genus Roseovarius, for which the names Roseovarius halophilus sp. nov., Roseovarius salis sp. nov. and Roseovarius salincola sp. nov. are proposed. The type strains of the proposed novel species are SYSU LYC5161T (=KCTC 8554T=MCCC 1K09438T), SYSU LYC5162T (=KCTC 8555T=MCCC 1K09397T) and EGI FJ00037T (=KCTC 92252T=CGMCC 1.19400T).