Nibribacter flagellatus sp. nov., isolated from rhizosphere of Hibiscus syriacus and emended description of the genus Nibribacter.

A Gram-stain negative, aerobic, motile by flagella, rod-shaped strain (THG-T16) was isolated from rhizosphere of Hibiscus syriacus. Growth occurred at 10-40 °C (optimum 28-30 °C), at pH 6.0-8.0 (optimum 7.0) and at 0-1.0% NaCl (optimum 0%). Based on 16S rRNA gene sequence analysis, the near phylogenetic neighbours of strain THG-T16 were identified as Nibribacter koreensis KACC 16450 (98.6%), Rufibacter roseus KCTC 42217 (94.7%), Rufibacter immobilis CCTCC AB 2013351 (94.5%) and Rufibacter tibetensis CCTCC AB 208084 (94.4%). The DNA G+C content of strain THG-T16 was determined to be 46.7 mol%. DNA-DNA hybridization values between strain THG-T16 and N. koreensis KACC 16450, R. roseus KCTC 42217, R. immobilis CCTCC AB 2013351, R.tibetensis CCTCC AB 208084 were 33.5 ± 0.5% (31.7 ± 0.7% reciprocal analysis), 28.1 ± 0.2% (25.2 ± 0.2%), 17.1 ± 0.9% (10.2 ± 0.6%) and 8.1 ± 0.3% (5.2 ± 0.1%). The polar lipids were identified as phosphatidylethanolamine, two unidentified aminophospholipids, an unidentified aminolipid and three unidentified lipids. The quinone was identified as MK-7 and the polyamine as sym-homospermidine. The major fatty acids were identified as C ω5c, C ω6c, iso-C, summed feature 3 (C ω7c and/or C ω6c) and summed feature 4 (iso-C I and/or anteiso-C B). On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics, and DNA-DNA hybridization data, strain THG-T16 represents a novel species of the genus Nibribacter, for which the name Nibribacter flagellatus sp. nov. is proposed. The type strain is THG-T16(= KACC 19188 = CCTCC AB 2016246).