Poseidonocella pacifica gen. nov., sp. nov. and Poseidonocella sedimentorum sp. nov., novel alphaproteobacteria from the shallow sandy sediments of the Sea of Japan

The taxonomic study of two Gram-negative, aerobic, non-pigmented bacteria KMM 9010T and KMM 9023T isolated from a sandy sediment sample collected from the Sea of Japan seashore was performed. On the basis of the nearly complete 16S rRNA gene sequences, strains KMM 9010T and KMM 9023T clustered with the Roseobacter lineage (class Alphaproteobacteria) forming a distinct phylogenetic line adjacent to the genus Donghicola. Novel strains shared the highest sequence similarity of 96.4% to each other and lower than 96.1% similarities to other validly named genera of the class Alphaproteobacteria. In both strains, ubiquinone Q-10 was found to be the major respiratory quinone; phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidic acid, and an unknown aminolipid were the major polar lipids and C18:1ω7c and 11-methyl C18:1ω7c were predominant fatty acids. The DNA G+C content was 60.5 mol% (KMM 9010T) and 65.4 mol% (KMM 9023T). Based on phenotypic properties and phylogenetic evidence, strains KMM 9010T and KMM 9023T should be classified as two novel species in a new genus, Poseidonocella gen. nov., with Poseidonocella pacifica sp. nov., the type species with the type strain KMM 9010T (= NRIC 0794T = JCM 17310T), and Poseidonocella sedimentorum sp. nov. as the second species with the type strain KMM 9023T (= NRIC 0796T = JCM 17311T).