Roseomonas hibiscisoli sp. nov., isolated from the rhizosphere of Mugunghwa (Hibiscus syriacus)

A Gram-stain-negative, aerobic, non-motile and coccoid to short-rod-shaped bacterial strain (THG-N2.22T) was isolated from the rhizosphere of Mugunghwa (Hibiscus syriacus). Growth occurred at 20-40 °C (optimum 28 °C), at pH 5-9 (optimum 7) and with 0-4 % (w/v) NaCl (optimum 1 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-N2.22T were identified as Roseomonas rhizosphaerae YW11T (98.5 % similarity), Roseomonas rubra S5T (98.5 %), Roseomonas cervicalis ATCC 49957T (98.2 %), Roseomonas aestuarii JC17T (97.8 %), Roseomonas oryzae JC288T (97.3 %) and Roseomonas ludipueritiae 170/96T (97.3 %); levels of similarity with the type strains of other Roseomonas species were lower than 97.0 %. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, two unidentified aminolipids, three unidentified phospholipids and three unidentified lipids. The major quinone was ubiquinone-10. The major fatty acids were C16 : 0, C18 : 1 2-OH, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The DNA G+C content of strain THG-N2.22T was 64.1 mol%. DNA-DNA hybridization values between strain THG-N2.22T and R. rhizosphaerae YW11T, R. rubra S5T, R. cervicalis ATCC 49957T, R. aestuarii JC17T, R. oryzae JC288T and R. ludipueritiae 170/96T were 43.1 % (30.2 %, reciprocal analysis), 39.0 % (24.7 %), 34.4 % (15.2 %), 18.0 % (14.5 %), 14.7 % (9.7 %) and 11.0 % (5.6 %), respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-N2.22T represents a novel species of the genus Roseomonas, for which the name Roseomonas hibiscisoli sp. nov. is proposed. The type strain is THG-N2.22T (=KACC 18935T=CCTCC AB 2016176T).