Palleronia abyssalis sp nov., isolated from the deep Mediterranean Sea and the emended description of the genus Palleronia and of the species Palleronia marisminoris

Three strains designated 221-F1(T), 221-F2 and 3030-F1 were isolated from the Matapan Vavilov Deep canyon, also known as Calypso Deep in the Eastern Mediterranean Sea, at a depth of 4,908 m. Based on 16S rRNA gene sequence analysis these strains were found to be most closely related to Palleronia marisminoris and Hwanghaeicola aestuarii, with 16S rRNA gene pairwise sequence similarity of 95.3 and 94.7 % respectively, belonging to the family Rhodobacteraceae. The strains were observed to be red-pigmented and to form non-motile cocci or pleomorphic cells. The cells were found to stain Gram-negative, to be strictly aerobic, oxidase and catalase positive. Strains 221-F1(T), 221-F2 and 3030-F1 were found to be mesophilic and to grow in medium containing up to 13 % NaCl. The major polar lipids of the three strains were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, an unidentified glycolipid and an unidentified aminolipid. Ubiquinone 10 (U-10) was found to be the major respiratory quinone. The DNA G+C content of strain 221-F1(T) was determined to be 64.7 mol%. Based on phylogenetic, physiological and biochemical characteristics we describe a new species represented by strain 221-F1(T) (=CECT 8504(T) = LMG 27977(T)) for which we propose the name Palleronia abyssalis sp. nov. We also propose to emend the description of the genus Palleronia and the species P. marisminoris to reflect new results obtained in this study.