Nocardioides okcheonensis sp. nov., isolated from riverside soil

An actinobacterial strain designated MMS20-HV4- 12(T), displaying a high hydrolytic potential for various substrates, was isolated from a riverside soil sample and characterized by polyphasic taxonomic analysis. Growth occurred at 10-37 degrees C (optimum, 30 degrees C), with NaCl concentrations of 0-4% (optimum, 0%) and at pH 7-9 (optimum, pH 8). MMS20-HV4- 12(T) was catalase-positive, oxidase-negative, rod-shaped and formed creamy white-coloured colonies. Based on the results of 16S rRNA gene sequence analysis, MMS20-HV4- 12(T) was found to be mostly related to the type strains of Nocardioides alpinus (98.3% sequence similarity), Nocardioides furvisabuli (98.1 %) and Nocardioides zeicaulis (98.0 %). MMS20-HV4- 12(T) showed optimal growth on Reaoner's 2A agar, forming white-coloured colonies. The diagnostic polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol, the major fatty acids were iso-C-16:0, C-17 :1 omega 8c and 10-methyl- C-17:0, the major isoprenoid quinone was MK-8( H-4), the diagnostic cell-wall sugar was galactose, and the cell-wall diamino acid was ll-diaminopimelic acid. The genome of MMS20-HV4- 12(T) was 4.47 Mbp in size with a G+C content of 72.9 mol%. The genome based analysis indicated low relatedness between MMS20-HV4- 12T and all compared species of Nocardioides, as the highest digital DNA-DNA hybridization and the orthologous average nucleotide identity values were 26.8 and 83.8% respectively. Based on genotypic, phenotypic and phylogenomic characterization, MMS20-HV4- 12(T) evidently represents a novel species of genus Nocardioides, for which the name Nocardioides okcheonensis sp. nov. (type strain=MMS20-HV4- 12(T)= KCTC 49651(T)=LMG 32360(T)) is proposed.

Automated summary

A novel actinobacterial strain, designated MMS20-HV4-12(T), with high hydrolytic potential, was isolated and characterized from a riverside soil sample. It showed optimal growth at 30 degrees C, without NaCl tolerance, and at pH 8. Based on the analysis of 16S rRNA gene sequence, it was identified as a new species of the genus Nocardioides, named Nocardioides okcheonensis sp. nov.