Cohnella plantaginis sp. nov., a novel nitrogen-fixing species isolated from plantain rhizosphere soil

A novel bacterium capable of fixing nitrogen was isolated from plantain rhizosphere soil in China. The isolate, designated YN-83T, is Gram-positive, aerobic, motile and rod-shaped (0.4–0.6 μm × 1.9–2.6 μm). Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain YN-83T was a member of the genus Cohnella. High similarity of 16S rRNA gene sequence was found between YN-83T and Cohnella ginsengisoli DSM18997T (97.99%), whereas the similarity was below 96.0% between YN-83T and the other Cohnella species. DNA–DNA relatedness between strain YN-83T and C. ginsengisoli DSM18997T was 27.4 ± 6.2%. The DNA G+C content of strain YN-83T was 59.3 mol%. The predominant isoprenoid quinone was MK-7 and the major fatty acids were anteiso-C15:0 (44.3%), iso-C15:0 (11.3%), iso-C16:0 (18.6%) and C16:0 (7.7%). The polar lipids of strain YN-83T consist of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, lyso- phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. On the basis of phenotypic and chemotaxonomic properties, 16S rRNA gene sequence, G+C content and DNA–DNA hybridization, strain YN-83T represents a novel species of the genus Cohnella, for which the name Cohnella plantaginis sp. nov. (type strain YN-83T = DSM 25424T = CGMCC 1.12047T) is proposed.