Arthrobacter mangrovi sp. nov., an actinobacterium isolated from the rhizosphere of a mangrove

A novel actinobacterium, designated HIs16- 36(T), was isolated from the rhizosphere of a mangrove on Ishigaki Island, Okinawa, Japan, and its taxonomic position was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain HIs16- 36(T )was closely related to the members of the genus Arthrobacter. The highest 16S rRNA gene sequence similarity was observed with Arthrobacter crystallopoietes (98.5 %), followed by Arthrobacter globiformis (97.2 %). The peptidoglycan of strain HIs16- 36(T) was of the A4a type, with lysine as the diagnostic diamino acid. The predominant isoprenoid quinone was MK -9(H-2) and the major fatty acids were anteiso- C-15: 0 and iso-C-15:0. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two glycolipids. These chemotaxonomic features corresponded to those of the genus Arthrobacter. Meanwhile, the differences in some phenotypic characteristics, along with the results of average nucleotide identity and digital DNA-DNA hybridization analyses, indicated that strain HIs16- 36T should be distinguished from the recognized species of the genus Arthrobacter. Therefore, strain HIs16- 36T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter mangrovi sp. nov. is proposed. The type strain is HIs16- 36(T) (=NBRC 112813(T)=TBRC 15750(T)).