Chitinophaga chungangae sp. nov., isolated from a Korean grape garden and its potential to biosynthesize ginsenoside Rg2

Abstract

A ginsenoside Rg2-producing, Gram stain-negative, aerobic, catalase and oxidase-positive, rod-shaped, non-motile and orange pigmented novel bacterium designated strain MAH-28 ^T was isolated from soil sample of a grape garden. Strain MAH-28 ^T hydrolyzed aesculin, casein and DNA. Flexirubin-type pigments are present. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain MAH-28 ^T formed a cluster within the genus Chitinophaga and the most close relatives were Chitinophaga alhagiae T22^T (98.9% 16S rRNA gene sequence similarity), Chitinophaga humicola Ktm-2 ^T (98.8%), Chitinophaga barathri YLT18^T (98.3%) and Chitinophaga lutea ZY74^T (97.4%). The novel strain MAH-28 ^T has a draft genome size of 6,043,180 bp (14 contigs), annotated with 4,863 protein-coding genes, 53 tRNA and 6 rRNA genes. The ANI and dDDH values between strain MAH-28 ^T and the closely related type strains were in the range of 76.0-83.4% and 20.3-26.7%, respectively. The novel strain MAH-28 ^T was able to synthesize ginsenoside Rg2 from major ginsenoside Re. The genome annotation revealed 152 carbohydrate genes which may involve with the synthesis of ginsenoside Rg2. The respiratory quinone of strain MAH-28 ^T was MK-7 and the dominant cellular fatty acids were C_{15:0 iso}, C_16:1 ω5c and C_{17:0 iso} 3-OH. The DNA G + C content of strain MAH-28 ^T was 53.3 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic studies, strain MAH-28 ^T represents a new member of genus Chitinophaga for which the name Chitinophaga chungangae sp. nov. is proposed with type strain MAH-28 ^T (= KACC 19968 ^T = CGMCC 1.16605 ^T).

Keywords: Chitinophaga chungangae; Draft genome; Ginsenoside Rg2; Gram staining negative.