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

Abstract

A Gram-stain-negative, coccobacilli-shaped bacterium, designated YC6724(T), was isolated from the rhizosphere of rice in Jinju, Korea. The taxonomy of strain YC6724(T) was studied using a polyphasic approach. Strain YC6724(T) grew optimally at 30 degrees C and pH 7.0-8.0. Comparative 16S rRNA gene sequence analyses showed that the strain was most closely related to Roseomonas soli 5N26(T) (98.4 % 16S rRNA gene sequence similarity), Roseomonas lacus TH-G33(T) (97.3 %) and Roseomonas terrae DS-48(T) (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 YC6724(T) formed a distinct phyletic lineage within the genus Roseomonas. Strain YC6724(T) had DNA DNA relatedness values of 16.6 %, 44.0 % and 33.2 % with R. soli KACC 16376(T), R. terrae KACC 126771 and R. lacus KACC 11678(T), respectively. The predominant fatty acids of strain YC6724(T) were C-18 (:) (1)omega 7c and/or C-18 (:) (1)omega 6c, C-16 (:) (0) and C-18 (:) (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 YC6724(T) contained spermidine as the major polyamine. On the basis of phenotypic, chemotaxonomic and molecular data, it is clear that strain YC6724(T) represents a novel species of the genus Roseomonas, for which the name Roseomonas oryzicola sp. nov. is proposed. The type strain is YC6724(T) (=KCTC 22478(T)=NBRC 109439(T)).