Flavobacterium tagetis sp. nov., a novel urea-hydrolysing bacterium isolated from the roots of Tagetes patula

초록

A Gram-stain-negative, rod-shaped, motile by gliding, non-sporulating and strictly aerobic bacterium, designated strain GN10(T), was isolated from the roots of Tagetes patula, collected from the garden of Dongguk University, Goyang, Republic of Korea. The cells could grow at 10-42 degrees C and at pH 5.5-9.0. Strain GN10(T) was sensitive to NaCl and tolerated up to 4 % NaCl (w/v). Com-parative analysis of 16S rRNA gene sequences revealed the highest similarities to Flavobacterium tistrianum GB 56.1(T) (98.9 %), Flavobacterium sharifuzzamanii A7.6(T) (98.6 %), Flavobacterium zhairuonense A5.7(T) (98.3 %) and Flavobacterium anhuiense D3(T) (98 %). Phylogenetic analysis showed that strain GN10(T) clustered within the genus Flavobacterium and formed a monophyletic cluster with its close relative members. The average nucleotide identity and digital DNA-DNA hybridization values between strain GN10(T) and related species belonging to the genus Flavobacterium were well below the standard threshold for prokaryotic species delineation. The DNA G+C content of strain GN10(T) was 33.6 mol%. The predominant cellular fatty acids (>10 %) were identified as iso-C-15:0, C-16:0 and summed feature 3 (C-16:1 omega 6c and/or C-16:1 omega 7c). Strain GN10(T) contained menaquinone 6 as the major respiratory quinone. The major polar lipids were phosphatidylethanolamine, three unidentified aminoglycolipids, two unidentified glycolipids, one unidentified phosphoglycolipid and five unidentified lipids. Urease is a nickel-containing enzyme found in archaea, bacteria, plants and unicellular eukaryotes. It serves as a virulence factor and is responsible for pathogenesis in humans and animals. Here, we describe a novel urease-hydrolysing bacterium, strain GN10(T). The urease activity of this strain may serve as an indicator of pathogenic potential and drug resistance, which may facilitate the development of many diseases. The results of physiological and biochemical tests allowed the genotypic and phenotypic differentiation of strain GN10(T) from its closely related members and considered to represent novel species in the genus Flavobacterium, for which the name Flavobac-terium tagetis (GN10(T)=KCTC 82695(T)=NBRC 114841(T)) is proposed.

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