Abstract

Three novel strains, (D17T, D13, and D25T) isolated from the gut of the Korean dark sleeper (Odontobutis platycephala), Kumgang fat minnow (Rhynchocypris kumgangensis), and the Korean oily bitterling (Tanakia koreensis) were identified as two novel species. Strains D17T and D13 showed the highest similarities in 16S rRNA gene and complete genome sequences to Deefgea rivuli WB 3.4-79T (98.0% and 97.9%, respectively, of 16S rRNA gene sequence similarity, 77.8% and 77.7%, respectively, of orthologous average nucleotide identity, Ortho- ANI, and 21.9% and 21.9%, respectively, of digital DNA-DNA hybridization, dDDH). Strain D17T showed the highest similarities in 16S rRNA gene and complete genome sequences to D13 (99.9% of 16S rRNA gene sequence similarity, 91.8% of OrthoANI, and 45.1% of dDDH); therefore, strains D17T and D13 were assigned as the same species. Strain D25T showed the highest similarities in 16S rRNA gene and complete genome sequences to D. chitinilytica Nsw-4T (98.2% of 16S rRNA gene sequence similarity, 82.4% of OrthoANI, and 25.1% of dDDH). Strains D17T and D13 were Gram-stain-negative, facultative anaerobes, rod-shaped, non-motile, and non-flagellated. Strain D25T was Gram-stain-negative, facultative anaerobe, rodshaped, and motile by a single polar flagellum. These strains had C16:0 and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) as the major cellular fatty acids and possessed Q-8 as a major respiratory ubiquinone. All three strains contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. Based on polyphasic taxonomic data, strains D17T, D13, and D25T represent two novel species of the genus Deefgea. We propose the name Deefgea piscis sp. nov. for strains D17T (= KCTC 82958T = JCM 34941T) and D13 (= KCTC 92368), and Deefgea tanakiae sp. nov. for strain D25T (= KCTC 82959T = JCM 34942T).

• Keywords: Genomic characteristics;Ornithinimicrobium cryptoxanthini;Sediment;Taxonomy;β-cryptoxanthin