A Gram-stain-negative, rod-shaped bacterium, strain 4-12T, was isolated from the rhizosphere of Triticum aestivum L. from the Xiaokai River irrigation area, China. The isolate grew optimally at 30 °C, pH 7.5-8.0 and with 1.0 % (w/v) NaCl. Based on the 16S rRNA gene sequence and phylogenetic analysis, strain 4-12T belonged to the genus Luteimonas with the highest degree of 16S rRNA gene sequence similarity to Luteimonas tolerans UM1T (97.68 %), followed by Luteimonas terrae THG-MD21T (97.67 %), Lysobacter panaciterrae Gsoil 068T (97.21 %) and Luteimonas aestuarii B9T (97.16 %). However, the DNA-DNA relatedness values between strain 4-12T and closely related Luteimonas strains were well below 40 %. The average nucleotide identity and the Genome-to-Genome Distance Calculator also showed low relatedness (below 95 and 70 %, respectively) between strain 4-12T and the type strains in genus Luteimonas. Ubiquinone-8 was the predominant quinone. The major fatty acids were iso-C15 : 0, iso-C11 : 0, iso-C17 : 0 and iso-C17 : 1ω9c. Polar lipids were dominated by diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and unidentified phospholipids. The DNA G+C content was 69.5 %. According to the phenotypic, genetic and chemotaxonomic data, strain 4-12T is considered to represent a novel species in the genus Luteimonas, for which the name >Luteimonas rhizosphaerae sp. nov. is proposed, with strain 4-12T (=CCTCC AB 2016261T=KCTC 52585T) as the type strain.
Keywords: Luteimonas; Rhizosphere soil; novel bacterium.