Planosporangium spinosum sp. nov., a novel actinobacterium isolated from tropical peat swamp forest soil in Rayong province of Thailand

A novel actinobacterium, designated strain 12N6^T, was isolated from tropical peat swamp forest soil in Rayong Province, Thailand. The taxonomic position was determined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 12N6^T was classified within the genus <i>Planosporangium</i> and showed the highest percentage similarity to <i>Planosporangium flavigriseum</i> YIM 46034^T (98.7%), followed by <i>Planosporangium thailandense</i> HSS8-18^T (98.0%) and <i>Planosporangium mesophilum</i> YIM 48875^T (97.9%). Strain 12N6^T produced a single globose spore with a spiny surface on short sporophores of the substrate mycelia. The approximate genome size and DNA G+C content of strain 12N6^T were 7.47 Mbp and 71.6 mol%, respectively. The highest average nucleotide identity and digital DNA-DNA hybridization values of genome sequences of 12N6^T compared with closest species type strains (83.0% and 27.8%, respectively) are well below the thresholds for species delineation. The whole-cell hydrolysates of strain 12N6^T contained <i>meso</i>-diaminopimelic acid, glucose, mannose, arabinose, xylose and ribose. The polar lipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The major cellular fatty acids were anteiso-C_{17 : 0}, iso-C_{16 : 0} and iso-C_{15 : 0}. The analysis of phylogenetic, genomic, phenotypic and chemotaxonomic characteristics revealed that strain 12N6^T is considered to represent a novel species of the genus <i>Planosporangium</i>, for which the name <i>Planosporangium spinosum</i> sp. nov. is proposed. The type strain is 12N6^T (=TBRC 19149^T=NBRC 117121^T).