Paracoccus hibisci sp. nov., isolated from the rhizosphere of Hibiscus syriacus L. (Mugunghwa flower).

Abstract

A Gram-stain-negative, aerobic, short-rod-shaped bacterium, motile by means of one flagellum (THG-T2.8T), was isolated from the rhizosphere of Mugunghwa flower. Growth occurred at 10-37 °C (optimum 28 °C), at pH 6-8 (optimum 7) and with 0-5 % NaCl (optimum 1 %). The major quinone was ubiquinone-10 (Q-10). The major fatty acids were C10 : 0 3-OH, C16 : 0, C18 : 0 and C18 : 1ω7c. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminolipid, two unknown phospholipids, one unknown glycolipid and one unidentified lipid. The DNA G+C content of strain THG-T2.8T was 65.5 mol%. Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T2.8T were identified as Paracoccus tibetensis Tibet-S9a3T (98.6 %), Paracoccus aestuarii B7T (98.4 %), Paracoccus rhizosphaerae CC-CCM15-8T (98.3 %) and Paracoccus beibuensis JLT1284T (98.2 %). Levels of sequence similarity among strain THG-T2.8T and other species of the genus Paracoccus were lower than 98.0 %. DNA-DNA hybridization values between strain THG-T2.8T and P. tibetensis Tibet-S9A3TT, P. aestuarii B7T, P. rhizosphaerae CC-CCM15-8T and P. beibuensisJLT1284T were 36.5 % (38.8 %, reciprocal analysis), 32.8 % (34.8 %), 31.6 % (33.8 %) and 15.3 % (24.8 %), respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T2.8T represents a novel species of the genus Paracoccus, for which the name Paracoccus hibisci sp. nov. is proposed. The type strain is THG-T2.8T (=KACC 18932T=CCTCC AB 2016181T).