Roseomonas oryzicola sp. nov., isolated from the rhizosphere of rice (Oryza sativa L.).

A Gram-stain-negative, coccobacilli-shaped bacterium, designated YC6724T, was isolated from the rhizosphere of rice in Jinju, Korea. The taxonomy of strain YC6724T was studied using a polyphasic approach. Strain YC6724T grew optimally at 30 °C and pH 7.0-8.0. Comparative 16S rRNA gene sequence analyses showed that the strain was most closely related to Roseomonas soli 5N26T (98.4 % 16S rRNA gene sequence similarity), Roseomonas lacus THG33T(97.3 %) and Roseomonas terrae DS-48T (97.3 %). Sequence similarities with other species of the genus Roseomonas with validly published names were lower than 94.0 %. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain YC6724T formed a distinct phyletic lineage within the genus Roseomonas. Strain YC6724T had DNA-DNA relatedness values of 16.6 %, 44.0 % and 33.2 % with R. soli KACC 16376T, R. terrae KACC 12677T and R. lacus KACC 11678T, respectively. The predominant fatty acids of strain YC6724T were C18 : 1ω7c and/or C18 : 1ω6c, C16 : 0 and C18 : 1 2-OH. The polar lipid profile contained phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol,diphosphatidylglycerol, an unknown aminolipid and two unknown lipids. The G+C content of the genomic DNA was 70.5 mol% and the major quinone was Q-10. Strain YC6724T contained spermidine as the major polyamine. On the basis of phenotypic, chemotaxonomic and molecular data, it is clear that strain YC6724T represents a novel species of the genus Roseomonas, for which the name Roseomonas oryzicola sp. nov. is proposed. The type strain is YC6724T (=KCTC 22478T=NBRC 109439T).