Fluviicola chungangensis sp. nov., a bacterium isolated from rice field

Abstract

A Gram-stain negative, aerobic, motile and rod-shaped novel bacterial strain, designated MAH-3(T), was isolated from soil sample of a rice field. The colonies were orange pigmented, smooth, circular and 0.4-0.9 mm in diameter when grown on R2A agar for 3 days. Strain MAH-3(T) was found to grow at 10-40 degrees C (optimum 30 degrees C), pH 6.0-8.0 (optimum 7.0) and in the presence of 0-1.0% NaCl (optimum 0%). Cell growth occurs on R2A agar and Luria-Bertani agar, but not on nutrient agar, tryptone soya agar and MacConkey agar. Cells were positive for catalase test but negative for oxidase test. Cells were able to hydrolyze casein, gelatin, DNA and Tween 80. 16S rRNA gene sequence analysis revealed that strain MAH-3(T) was most closely related to the genus Fluviicola and exhibited the highest sequence similarity to Fluviicola hefeinensis MYL-8(T) (97.4%), Fluviicola taffensis RW262(T) (96.2%) and Fluviicola kyonggii CA-1(T) (95.6%). Strain MAH-3(T) had a genome size of 4,271,694 bp and the genomic DNA G + C content was determined to be 41.7 mol%. The genome contained 19 contigs encoded by 3,664 protein-coding genes with 34 tRNA and 4 rRNA genes. The genomic ANI value between strain MAH-3(T) and one of the closely related type strains, F. taffensis DSM 16823(T) was 76.2%. The predominant isoprenoid quinone of isolated strain MAH-3(T) was menaquinone-6 (MK-6). The major fatty acids were identified as C-15:0 iso, C-15:0 2OH and C-17:0 iso 3OH. On the basis of these phenotypic, genotypic and chemotaxonomic studies and DNA-DNA hybridization results, the isolated strain MAH-3(T) represents a novel species, for which the name Fluviicola chungangensis sp. nov. is proposed, with MAH-3(T) as the type strain (= KACC 19742(T) = CGMCC 1.13750(T)).