Paracoccus rhizosphaerae sp. nov., isolated from the rhizosphere of the plant Crossostephium chinense (L.) Makino (Seremban)

Abstract

A Gram-negative, coccoid-shaped bacterium, strain CC-CCM15-8T, was isolated from a rhizosphere soil sample of the plant Crossostephium chinense (L.) Makino (Seremban) from Budai Township, Chiayi County, Taiwan. 16S rRNA gene sequence analysis clearly allocated strain CC-CCM15-8T to the Paracoccus cluster, showing highest similarities to the type strains of ‘Paracoccus beibuensis’ (98.8 %), Paracoccus homiensis (97.6 %), Paracoccus aestuarii (97.7 %) and Paracoccus zeaxanthinifaciens (97.7 %). The fatty acid profile, comprising C18 : 1ω7c as the major component and C10 : 0 3-OH as the characteristic hydroxylated fatty acid, supported the placement of strain CC-CCM15-8T within the genus Paracoccus . The polyamine pattern consisted of putrescine and spermidine as major components. Ubiqinone Q-10 was the major quinone type (95 %); ubiquinone Q-9 was also detected (5 %). The complex polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, and unidentified phospholipids, lipids and glycolipids. Levels of DNA–DNA relatedness between strain CC-CCM15-8T and ‘P. beibuensis’ LMG 25871T, P. aestuarii DSM 19484T, P. zeaxanthinifaciens LMG 21993T and P. homiensis KACC 11518T were 24.9 % (34.8 %, reciprocal analysis), 15.7 % (17.5 %), 17.7 % (23.4 %) and 16.0 % (25.4 %), respectively. Physiological and biochemical test results allowed the phenotypic differentiation of strain CC-CCM15-8T from its closest relatives in the genus Paracoccus . Based on the data presented, it is concluded that strain CC-CCM15-8T represents a novel species of the genus Paracoccus , for which the name Paracoccus rhizosphaerae sp. nov. is proposed. The type strain is CC-CCM15-8T ( = LMG 26205T = CCM 7904T).