Description of Deefgea piscis sp. nov., and Deefgea tanakiae sp. nov., isolated from the gut of Korean indigenous fish

Three novel strains, (D17(T), D13, and D25(T)) 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 D17(T) and D13 showed the highest similarities in 16S rRNA gene and complete genome sequences to Deefgea rivuli WB 3.4–79(T) (98.0% and 97.9%, respectively, of 16S rRNA gene sequence similarity, 77.8% and 77.7%, respectively, of orthologous average nucleotide identity, OrthoANI, and 21.9% and 21.9%, respectively, of digital DNA-DNA hybridization, dDDH). Strain D17(T) 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 D17(T) and D13 were assigned as the same species. Strain D25(T) showed the highest similarities in 16S rRNA gene and complete genome sequences to D. chitinilytica Nsw-4(T) (98.2% of 16S rRNA gene sequence similarity, 82.4% of OrthoANI, and 25.1% of dDDH). Strains D17(T) and D13 were Gram-stain-negative, facultative anaerobes, rod-shaped, non-motile, and non-flagellated. Strain D25(T) was Gram-stain-negative, facultative anaerobe, rod-shaped, and motile by a single polar flagellum. These strains had C(16:0) and summed feature 3 (C(16:1)ω7c and/or C(16:1)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 D17(T), D13, and D25(T) represent two novel species of the genus Deefgea. We propose the name Deefgea piscis sp. nov. for strains D17(T) (= KCTC 82958(T) = JCM 34941(T)) and D13 (= KCTC 92368), and Deefgea tanakiae sp. nov. for strain D25(T) (= KCTC 82959(T) = JCM 34942(T)). Supplemental material for this article may be found at 10.1007/s12275-022-2250-5.