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

Abstract

Two novel strains, designated APW6T and APW11T, were isolated from artificial pond water, and one novel strain, designated PFR6T, 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: APW6T, 15–43 °C (optimum, 28 °C), pH 6.0–12.0 (optimum, pH 7.0), with no salinity; APW11T, 4–35 °C (optimum, 25 °C), pH 6.0–11.0 (optimum, pH 9.0), with 0–1 % NaCl (w/v, optimum 0 %); PFR6T, 10–38 °C (optimum 28 °C), pH 6.0–12.0 (optimum, pH 7.0), with 0–2 % NaCl (w/v; optimum, 0 %). Strains APW6T, APW11T, and PFR6T belonged to the genus Roseateles, having the most 16S rRNA gene sequence similarity to Roseateles saccharophilus DSM 654T (98.1 %), Roseateles oligotrophus CHU3T (98.7 %), and Roseateles puraquae CCUG 52769T (98.1 %). The estimated genome sizes of APW6T, APW11T, and PFR6T 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 C16: 1 ω6c and/or C16: 1 ω7c) and C16: 0. PFR6T also had summed feature 8 (comprising C18: 1 ω7c and/or C18: 1 ω6c) 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 APW6T, APW11T, and PFR6T represent novel species within the genus Roseateles, for which the names Roseateles subflavus sp. nov., with the type strain APW6T (=KACC 22877T=TBRC 16606T), Roseateles aquae sp. nov., with the type strain APW11T (=KACC 22878T=TBRC 16607T), and Roseateles violae sp. nov (=KACC 23257T=TBRC 17653T) are respectively proposed. © 2024 The Authors.