Dokdonella aquatica sp. nov., isolated from freshwater

A Gram-stain-negative, strictly aerobic, non-motile, non-flagellated and rod-shaped bacterium, strain MW10^T, was isolated from freshwater in South Korea. The strain exhibited catalase-negative and oxidase-positive activities and grew at 15-35 °C (optimum, 25 °C), pH 6.0-9.0 (optimum, 7.0) and in 0-3.0% (w/v) NaCl (optimum, 0%). Ubiquinone-8 was the sole respiratory quinone, and the major cellular fatty acids (>10%) were iso-C_15 : 0, iso-C_16 : 0 and summed feature 9 (iso-C_17 : 1  ω9c and/or C_16 : 0 10-methyl). Polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminophospholipid and an unidentified glycolipid. The genome of strain MW10^T was 4831 kb in size with a DNA G+C content of 69.0 mol%. Strain MW10^T was most closely related to Dokdonella immobilis LM 2-5^T and Dokdonella koreensis DS-123^T with 16S rRNA gene sequence similarities of 97.1% and 96.0%, respectively. Phylogenetic analyses based on 16S rRNA gene and 120 marker protein sequences placed strain MW10^T within the genus Dokdonella as a distinct lineage. Average nucleotide identity and digital DNA-DNA hybridization values between strain MW10^T and related type strains were ≤76.6% and ≤21.1%, respectively. Collectively, phylogenetic, genomic, phenotypic and chemotaxonomic evidence support the conclusion that strain MW10^T represents a novel species of the genus Dokdonella, for which the name Dokdonella aquatica sp. nov. is proposed. The type strain is MW10^T (=KACC 23687^T=JCM 36943^T).