Two Gram-positive, aerobic, non-motile and non-spore-forming actinobacteria, strains GY074T and GY239T, were isolated from deep-sea sediment of the Southern Atlantic Ocean. The results of phylogenetic analysis of 16S rRNA gene sequences placed both isolates within the genus Nesterenkonia, and showed a sequence similarity of 98.3 % between the two strains and similarites of 94.3-97.2 % with respect to Nesterenkonia species with validly published names. Based on whole-genome sequences, the values of in silico DNA-DNA hybridization and the average nucleotide identity between strains GY074T and GY239T were 21.2 and 78.1 %, respectively, less than the proposed cut-off level for species delineation, i.e. 70 and 95 %. For both strains, the major cellular fatty acids were anteiso-C17 : 0 and anteiso-C15 : 0, and the major menaquinones were MK-7, MK-8 and MK-9. The major polar lipid contents of the two strains were similar with phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid. The genomic DNA G+C contents of strains GY074T and GY239T were 61.1 and 64.2 mol%, respectively. On the basis of the phylogenetic analysis and physiological and chemotaxonomic data, the isolates represent two novel species of the genus Nesterenkonia, for which the names Nesterenkonia salmonea sp. nov. (type strain GY074T=KCTC 39639T=MCCC 1A11256T) and Nesterenkonia sphaerica sp. nov. (type strain GY239T=KCTC 39640T=MCCC 1A10688T) are proposed.
Keywords: Nesterenkonia salmonea sp. nov.; Nesterenkonia sphaerica sp. nov.; marine sediment; polyphasic taxonomy.