Two Gram-stain-negative, oxidase- and catalase-positive, aerobic strains (CY05T and H18S-6) were isolated from sediment samples of the Yellow Sea, China. The strains were positive for denitrification. Optimum growth was observed at 20 °C, pH 7.5-8.0 and with 2.0%-3.0% NaCl. The predominant cellular fatty acids (> 10%) were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), major respiratory quinone was ubiquinone-10 and main polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and one unidentified aminolipid. The approximate genome size of strains CY05T and H18S-6 were 4.86 and 5.04 Mbp, the genomic G + C content of them were 54.2 and 54.5%, respectively. Both of the phylogenetic analysis based on 16S rRNA gene sequences and the up-to-date bacterial core gene (UBCG) sequences revealed that strains CY05T, H18S-6 and Pelagicola marinus DSW4-44T formed a distinct monophyletic clade within the family Rhodobacteraceae. The ANI and isDDH values between strains CY05T and H18S-6 were 94.0% and 56.5%, between CY05T and Pelagicola marinus DSW4-44T were 94.1% and 59.8%, respectively, all below the accepted threshold value for species delineation. But the ANI and isDDH values between strains H18S-6 and Pelagicola marinus DSW4-44T were 96.8% and 76.7% respectively, indicating that strains H18S-6 and Pelagicola marinus DSW4-44T belong to the same species. Based on the distinctive polyphasic evidence, CY05T represent a novel species of a novel genus of the family Rhodobacteraceae, for which the name Zongyanglinia huanghaiensis gen. nov., sp. nov. is proposed. The type strain is CY05T (= MCCC 1K04409T = KCTC 62200T). Moreover, the reclassification of Pelagicola marinus Choi et al. 2019 as Zongyanglinia marinus comb. nov. (type strain DSW4-44T = KCTC 62762T = KCCM 43261T = JCM 33637T) is proposed based on the polyphasic taxonomic data obtained in this study.
Keywords: Denitrification; Polyphasic taxonomy; Rhodobacteraceae; Zongyanglinia gen. nov..