Rhodococcus enclensis sp. nov., a novel member of the genus Rhodococcus

Abstract

A novel actinobacterial strain, designated, NIO-1009T, was isolated from a marine sediment sample collected from Chorao Island, Goa, India. Phylogenetic analysis comparisons based on 16S rRNA gene sequences between strain NIO-1009T and other members of the genus Rhodococcus revealed that strain NIO-1009T had the closest sequence similarity to Rhodococcus kroppenstedtii DSM 44908T and Rhodococcus corynebacterioides DSM 20151T with 99.2 and 99.1 %, respectively. Furthermore, DNA–DNA hybridization results showed that R. kroppenstedtii DSM 44908T and R. corynebacterioides DSM 20151T were 39.5 (3.0 %) and 41.7 (2.0 %) with strain NIO-1009T, respectively, which were well below the 70 % limit for any novel species proposal. Phylogenetically strain NIO-1009T forms a stable clade with and R. kroppenstedtii DSM 44908T and R. corynebacterioides DSM 20151T with 100 % bootstrap values. Strain NIO-1009T contained meso-diaminopimelic acid as the diagnostic diamino acid and galactose and arabinose as the cell wall sugars. The major fatty acids were C16 : 0, C18 : 1ω9c, C16 : 1(ω6c and/or ω7c) and 10-methyl C18 : 0. The only menaquinone detected was MK-8(H2), while the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and one unknown phospholipid. The G+C content of the genomic DNA was 66.9 mol%. The phenotypic and genotypic data showed that strain NIO-1009T warrants recognition as a novel species of the genus Rhodococcus for which the name Rhodococcus enclensis sp. nov., is proposed; the type strain is NIO-1009T ( = NCIM 5452T = DSM 45688T).