Flavobacterium dauae sp. nov., isolated from rhizosphere soil of a tomato plant

A bacterial strain, designated TCH3-2(T), was isolated from the rhizosphere of tomato plant grown at Dong-A University Agricultural Experiment Station, Republic of Korea. The strain was Gram-stain-negative, obligate aerobic, orange yellow-coloured, motile by gliding and short rod-shaped. Strain TCH3-2 (T) only grew on 1/2 tryptic soy agar and Luria-Bertani agar among the media tested, with optimum growth at 28 degrees C and pH 7. Salt of 1% NaCl was necessary to support the growth of TCH3-2(T). Strain TCH3-2(T) produced flexirubin-type pigments. The predominant cellular fatty acids were iso-C-15:0 (55.6%), iso-C-17:0 3-OH (17.9%), summed feature 9 (comprising C-16:0 10-methyl and/or iso-C-17:1 omega 9c; 10.5%), iso-C-15:0 3-OH (4.8%) and anteiso-C-15:0 (2.3 %). The major menaquinone was menaquinone-6 and the major polar lipids were phosphatidylethanolamine, five unknown aminolipids and three unknown lipids. Phylogenetic analysis based on 16S rRNA sequences indicated that TCH3-2(T) was closely related to Flavobacterium ummariense DS-12(T) (95.16 %), Flavobacterium marinum SW105(T) (95.14 %) and Flavobacterium viscosus YIM 102796(T) (94.54%). The draft genome of TCH3-2(T) comprised ca. 2.8 Mb with a G+C content of 34.61mol%. The average nucleotide identity and digital DNA-DNA hybridization values between TCH3-2(T) and closely related Flavobacterium species showed that it belongs to a distinct species. Furthermore, the results of morphological, physiological and biochemical tests allowed further phenotypic differentiation of TCH3-2(T) from its closest relatives. Thus, chemotaxonomic characteristics together with phylogenetic affiliation illustrate that TCH3-2(T) represents a novel species of the genus Flavobacterium, for which the name Flavobacterium dauae sp. nov. (type strain TCH3-2(T)=KACC 19054(T)=JCM 34025(T)) is proposed.

Automated summary

A novel bacterial strain, Flavobacterium dauae sp. nov., was isolated from the rhizosphere of tomato plant grown in South Korea. It showed distinctive physiological characteristics and genetic relationship within the Flavobacterium genus.