Pseudooceanicola atlanticus gen. nov. sp. nov., isolated from surface seawater of the Atlantic Ocean and reclassification of Oceanicola batsensis, Oceanicola marinus, Oceanicola nitratireducens, Oceanicola nanhaiensis, Oceanicola antarcticus and Oceanicola flagellatus, as Pseudooceanicola batsensis comb. nov., Pseudooceanicola marinus comb. nov., Pseudooceanicola nitratireducens comb. nov., Pseudooceanicola nanhaiensis comb. nov., Pseudooceanicola antarcticus comb. nov., and Pseudooceanicola flagellatus comb. nov.

Abstract

A taxonomic study was carried out on strain 22II-S11g(T), which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-negative, rod shaped without flagellum, oxidase positive and weakly catalase positive. Growth was observed at NaCl concentrations of 0.5-9% and at temperatures of 10-41°C. The isolate was incapable of gelatin hydrolysis and unable to reduce nitrate to nitrite, degrade aesculin and Tween 80. On the basis of 16S rRNA gene sequence similarity, strain 22II-S11g(T) was found to be most closely related to Oceanicola batsensis HTCC2597(T) (97.26%), followed by Oceanicola nitratireducens JLT1210(T) (96.39%), whilst other species of genus Oceanicola shared 94.00-96.34% sequence similarity. However, it showed low similarity to Oceanicola granulosus HTCC2516(T) (94.79%), the type species of the genus Oceanicola. Phylogenetic analysis showed that strain 22II-S11g(T) formed a clade with six species currently classified in the genus Oceanicola, but strain O. granulosus HTCC2516(T) and strain O. litoreus M-M22(T) clustered with two other genera respectively. The ANI values between strain 22II-S11g(T) and two type strains (O. batsensis HTCC2597(T) and O. granulosus HTCC2516(T)) are 91.86 and 91.81% respectively. The digital DNA-DNA hybridization estimate values between strain 22II-S11g(T) and two type strains (O. batsensis HTCC2597(T) and O. granulosus HTCC2516(T)) are 23.4±2.4 and 20.0±2.3%, respectively. The principal fatty acids were identified as summed feature 8 (C18:1 ω7c/ω6c), C16:0, C18:1 ω7c11-methyl and C12:0 3OH. The G+C content determined from the draft genome sequence is 64.1mol%. The respiratory quinone was determined to be Q-10 (100%). Phosphatidylethanolamine, phosphatidylglycerol, an aminolipid, phosphatidylcholine, a phospholipid and three lipids were identified in the polar lipids. The combined genotypic and phenotypic data also show that strain 22II-S11g(T) should not be assigned to the genus Oceanicola; consequently strain 22II-S11g(T) is concluded to represent a novel species of a novel genus in the family Rhodobacteraceae, for which the name Pseudooceanicola atlanticus gen. nov., sp. nov. is proposed (type strain 22II-S11g(T)=KCTC 42004(T)=LMG 27424(T)=MCCC 1A09160(T)). Six misclassified species should be transferred to the novel genus Pseudooceanicola as follows: O. batsensis should be transferred to the genus Pseudooceanicola as Pseudooceanicola batsensis comb. nov. (type strain HTCC2597(T)=ATCC BAA-863(T)=DSM 15984(T)=KCTC 12145(T)); Oceanicola marinus should be transferred to the genus Pseudooceanicola as Pseudooceanicola marinus comb. nov. (type strain AZO-C(T)=LMG 23705(T)=BCRC 17591(T)); O. nitratireducens should be transferred to the genus Pseudooceanicola as Pseudooceanicola nitratireducens comb. nov. (type strain JLT1210(T)=LMG 24663(T)=CGMCC 1.7292(T)); Oceanicola nanhaiensis should be transferred to the genus Pseudooceanicola as Pseudooceanicola nanhaiensis comb. nov. (type strain SS011B1-20(T)=LMG 23508(T)=CGMCC 1.6293(T)); Oceanicola antarcticus should be transferred to the genus Pseudooceanicola as Pseudooceanicola antarcticus comb. nov. (type strain Ar-45(T)=CGMCC 1.12662(T)=LMG 27868(T)); and Oceanicola flagellatus should be transferred to the genus Pseudooceanicola as Pseudooceanicola flagellatus comb. nov. (type strain DY470(T)=CGMCC 1.12664(T)=LMG 27871(T)).