Flavobacterium humi sp. nov., a flexirubin-type pigment producing bacterium, isolated from soil

Abstract

A yellow pigmented, Gram-stain-negative, strictly aerobic, rod-shaped, motile by means of gliding, catalase and oxidase positive bacterium, designated strain DS2-A^T, was isolated from soil. Growth was observed at 4-32°C (optimum, 28°C), pH 6-9 (optimum, 7.0), and with 0-0.25% (w/v) NaCl (optimum, 0%). Phylogenetic analysis of 16S rRNA gene sequence revealed that strain DS2-A^T belonged to the genus Flavobacterium and was most closely related to Flavobacterium aquatile LMG 4008^T (96.4%), Flavobacterium terrae DSM 18829^T (95.6%), Flavobacterium vireti THG-SM1^T (95.5%), Flavobacterium inkyongense IMCC27201^T (95.4%), Flavobacterium brevivitae TTM-43^T (95.2%), and Flavobacterium cucumis DSM 18830^T (95.2%). Strain DS2-A^T produces flexirubin-type pigments. The major fatty acids were iso-C_15:0, iso-C_17:0 3-OH, and iso-C_15:0 3-OH. The major respiratory quinone was identified as menaquinone-6. The major polar lipid was found to be phosphatidylethanolamine. The average nucleotide identity values between strain DS2-A^T and selected taxa, F. aquatile LMG 4008^T, F. terrae DSM 18829^T, and F. cucumis DSM 18830^T, were 72, 72.7, and 71.6%, respectively. The draft genome of strain DS2-A^T has a number of 14 contigs, scaffold N50 of 476,310 bp and a total size of 3,563,867 bp. Additionally, strain DS2-A^T contains 3,127 of gene, 41 of tRNA, 6 of rRNA, and 3 of ncRNA. The DNA G + C content of stain DS2-A^T was 40.7 mol%. Based on phylogenetic and phenotypic analyses, strain DS2-A^T is considered as a novel species of the genus Flavobacterium, for which the name Flavobacterium humi sp. nov., (type strain DS2-A^T = KACC 19715^T = JCM 32786^T) has been proposed.

Keywords: Flavobacterium humi; flexirubin-type pigment; gliding motility; polyphasic taxonomy; strictly aerobic.