Rhizobium wenxiniae sp nov., an endophytic bacterium isolated from maize root

A novel Gram-stain-negative, aerobic, rod-shaped strain designated 166(T) was isolated from surface-sterilized root tissue of maize planted in the Fangshan District of Beijing, PR China. The 16S rRNA gene sequence analysis indicated that strain 166(T) belongs to the genus Rhizobium and is closely related to Rhizobium cellulosilyticum ALA10B2(T) and Rhizobium yantingense H66(T) with sequence similarities of 98.8 and 98.3 %, respectively. According to atpD and recA sequence analysis, the highest sequence similarity between strain 166(T) and R. cellulosilyticum ALA10B2(T) is 93.8 and 84.7 %, respectively. However, the new isolate exhibited relatively low levels of DNA-DNA relatedness with respect to R. cellulosilyticum DSM 18291(T) (20.8 +/- 2.3 %) and Rhizobium yantingense CCTCC AB 2014007(T) (47.2 +/- 1.4 %). The DNA G+C content of strain 166(T) was 59.8 mol%. The main polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, an unidentified aminophospholipid and an unidentified aminolipid. The major fatty acids of strain 166 T were summed feature 8(C-18:1 omega 7c and/or C-18 : 1 omega 6c). The results of the physiological and biochemical tests and minor differences in the fatty acid profiles allowed a clear phenotypic differentiation of strain 166(T) from the type strains of closely related species, R. cellulosilyticum DSM 18291(T) and R. yantingense CCTCC AB 2014007(T). Strain 166 (T) represents a novel species within the genus Rhizobium, for which the name Rhizobium wenxiniae sp. nov. is proposed, with the type strain 166 (T) (= CGMCC 1.15279(T) = DSM 100734(T)).