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 LYC5161^T, SYSU LYC5162^T and EGI FJ00037^T, 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 <i>Roseovarius salinarum</i> N53^T, <i>Roseovarius amoyensis</i> GCL8^T and <i>Roseovarius halotolerans</i> DSM 29507^T from the genus <i>Roseovarius</i>. Based on the genome sequencing data, the G+C contents of strains SYSU LYC5161^T, SYSU LYC5162^T and EGI FJ00037^T 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 <i>Roseovarius</i> were below the cut-off values proposed for the delineation of a novel species. The novel isolates were distinguished from other <i>Roseovarius</i> 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 genu<i>s Roseovarius</i>, for which the names <i>Roseovarius halophilus</i> sp. nov., <i>Roseovarius salis</i> sp. nov. and <i>Roseovarius salincola</i> sp. nov. are proposed. The type strains of the proposed novel species are SYSU LYC5161^T (=KCTC 8554^T=MCCC 1K09438^T), SYSU LYC5162^T (=KCTC 8555^T=MCCC 1K09397^T) and EGI FJ00037^T (=KCTC 92252^T=CGMCC 1.19400^T).