A Gram-stain-negative, aerobic, non-motile, rod-shaped bacterial strain, designated CAU 1488T, was isolated from tidal flat sediment, and its taxonomic position was investigated using a polyphasic approach. The organism grew optimally at a temperature of 30 °C, at pH 7.0-7.5 and in the presence of 0-6 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1488T forms a lineage distinct from Ruegeria marisrubri ZGT 118T (97.9 %), Ruegeria marina ZH17T (97.6 %), Ruegeria lacuscaerulensis ITI 1157T (97.5 %), Ruegeria pomeroyi DSS-3T (97.1 %), Ruegeria profundi ZGT108T (97.0 %), Ruegeria intermedia CC-GIMAT-2T (96.8 %), Ruegeria atlantica CECT 4292T (96.7 %) and Ruegeria kandeliae J95T (95.9 %). Genome sequencing revealed that CAU 1488T had a genome size of 4.23 Mbp and a G+C content of 63.2 mol%. Overall genome related indexes including average nucleotide identity and digital DNA-DNA hybridization values were 75.0-83.0 % and 26.2 %, which are below the cutoffs of 95 and 70 %, respectively, indicating that strain CAU 1488T represents a distinct species from the members of the genus Ruegeria. The predominant quinone was ubiquinone-10 (Q-10). The major fatty acids were summed feature 8 (C18 : 1 ω7c/ω6c; 60.7 %) and its polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and unidentified aminolipids. On the basis of phenotypic, chemotaxonomic and genomic data, strain CAU 1488T constitutes a novel species of the genus Ruegeria, for which the name Ruegeria sediminis sp. nov. is proposed. The type strain is CAU 1488T (=KCTC 62996T=NBRC 113693T).
Keywords: Proteobacteria; Rhodobacteraceae; Ruegeria sediminis; tidal flat.