Azospirillum ramasamyi sp. nov., a novel diazotrophic bacterium isolated from fermented bovine products

A Gram-stain-negative, rod-shaped, aerobic bacterium, designated M2T2B2(T), was isolated from fermented bovine products in Suwon, Republic of Korea. The strain displayed growth at 15-45 degrees C (optimum, 28-30 degrees C), pH 6.0-10.0 (pH 7.0) and 0-2 % (w/v) NaCl (0 %). Colonies were light pink-coloured, round and convex. The cells were positive for oxidase and weakly positive for catalase. The major fatty acids in whole cells of strain M2T2B2(T) were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c), followed by summed feature 3 (C-16:1 omega 7c/C-16:1 omega 6c), summed feature 2 (C-12:0 aldehyde/unidentified 10.928/C-14:0 3-OH/iso-C16:1I), C-16(:0), C (18:1 )2-OH, C-16:0 3-OH and C-17(:1)omega 6c. The polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, and three unidentified aminolipids. Ubiquinone 10 was the predominant ubiquinone. The DNA G+C content was 68.0 mol%. The strain could fix atmospheric nitrogen, which was evaluated by the acetylene reduction assay. Further, whole genome sequence analysis revealed the presence of a nif gene cluster. Strain M2T2B2(T) showed the highest 16S rRNA, rpoD and nifH gene sequence similarity to members of the genus Azospirillum, and showed 97.6 % 16S rRNA gene sequence similarity to Azospirillum oryzae COC8(T). The phenotypic, phylogenetic and genomic analyses support the proposal of strain M2T2B2(T) as being a novel species of the genus Azospirillum, for which the name Azospirillum ramasamyi sp. nov. is proposed. The type strain is M2T2B2(T) (=KACC 14063(T) =NBRC 106460(T)).