Abstract:
A short coccoid- to rod-shaped, motile, mesophilic actinobacterium, strain MSL-22(T), was isolated from soil on Bigeum Island, Korea. A polyphasic study was undertaken to establish the taxonomic position of this strain. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MSL-22(T) formed an evolutionary lineage within the radiation of the genus Nocardioides. In particular, it formed a monophyletic lineage with Nocardioides jensenii KCTC 9134(T) with which it shared the highest sequence similarity of about 97.3%. However, DNA-DNA relatedness demonstrated that strain MSL-22(T) was distinct from its closest phylogenetic neighbours. The cell-wall peptidoglycan of strain MSL-22(T) contained LL-diaminopimelic acid. The predominant menaquinone was MK-8(H-4). Strain MSL-22(T) had a cellular fatty acid profile containing straight-chain, branched, unsaturated and 10-methyl fatty acids, with iso-C-16:0 as the major fatty acid. The DNA G+C content of the strain was 68.7 mol%. On the basis of phenotypic and phylogenetic evidence, the strain is separate from previously described members of the genus Nocardioides and represents a novel species in this genus, for which the name Nocardioides mesophilus sp. nov. is proposed. The type strain is MSL-22(T) (=DSM 19432(T)=KCTC 19310(T)).
