Roseateles subflavus sp. nov. and Roseateles aquae sp. nov., isolated from artificial pond water and Roseateles violae sp. nov., isolated from a Viola mandshurica root

Two novel strains, designated APW6 T and APW11 T , were isolated from artificial pond water, and one novel strain, designated PFR6 T , was isolated from a Viola mandshurica root. These strains were found to be Gram-negative, rod-shaped, motile by means of flagella, and oxidase-positive. Growth conditions of the type strains were as follows: APW6 T , 15–43 °C (optimum, 28 °C), pH 6.0–12.0 (optimum, pH 7.0), with no salinity; APW11 T , 4–35 °C (optimum, 25 °C), pH 6.0–11.0 (optimum, pH 9.0), with 0–1 % NaCl (w/v, optimum 0 %); PFR6 T , 10–38 °C (optimum 28 °C), pH 6.0–12.0 (optimum, pH 7.0), with 0–2 % NaCl (w/v; optimum, 0 %). Strains APW6 T , APW11 T , and PFR6 T belonged to the genus Roseateles , having the most 16S rRNA gene sequence similarity to Roseateles saccharophilus DSM 654 T (98.1 %), Roseateles oligotrophus CHU3 T (98.7 %), and Roseateles puraquae CCUG 52769 T (98.1 %). The estimated genome sizes of APW6 T , APW11 T , and PFR6 T were 50 50 473, 56 70 008, and 52 16 869 bp, respectively and the G+C contents were 69.5, 66, and 68.5 mol%. The digital DNA–DNA hybridization, average amino acid identity, and average nucleotide identity values among the novel strains and related taxa were all lower than 22.4, 74.7, and 78.9 %, respectively. The predominant cellular fatty acids (>10 %) of all strains were summed feature 3 (comprising C 16 : 1 ω 6 c and/or C 16 : 1 ω 7 c ) and C 16 : 0 . PFR6 T also had summed feature 8 (comprising C 18 : 1 ω 7 c and/or C 18 : 1 ω 6 c ) as a major fatty acid. The polar lipid profile of all strains contained phosphatidylethanolamine, phosphoaminoglycolipid, and phosphoglycolipid. The distinct phylogenetic, physiological, and chemotaxonomic features reported in this study indicate that strains APW6 T , APW11 T , and PFR6 T represent novel species within the genus Roseateles , for which the names Roseateles subflavus sp. nov., with the type strain APW6 T (=KACC 22877 T =TBRC 16606 T ), Roseateles aquae sp. nov., with the type strain APW11 T (=KACC 22878 T =TBRC 16607 T ), and Roseateles violae sp. nov (=KACC 23257 T =TBRC 17653 T ) are respectively proposed.