sp. nov., sp. nov. and sp. nov., endophytic actinobacteria isolated from wild orchid ( Roxb).

Three novel mycelium-forming actinobacteria, designated OC33-EN06, OC33-EN07, and OC33-EN08, were isolated from wild orchid ( Roxb), collected from a hill evergreen forest in Northern Thailand. Strains OC33-EN06 and OC33-EN07 showed the highest 16S rRNA gene similarity with TT00-04, 99.17 and 99.45%, respectively. Strain OC33-EN08 showed high similarity with four species, namely ' Odt1-22' (99.37%), DSM 45062 (99.02%), 014-5 (99.02%), and SF1 (98.81%). Comparative genome analysis of OC33-EN06, OC33-EN07, and OC33-EN08 with the closely related type strains showed that average nucleotide identity (ANI) based on blast, ANI based on MUMmer, and average amino acid identity values were less than 95% and the digital DNA-DNA hybridization values were less than 70%, all below the thresholds for species demarcation. The digital G+C content of OC33-EN06, OC33-EN07, and OC33-EN08 were 74.5, 74, and 74 mol%, respectively. These three strains developed bud-like chains of non-motile cylindrical spores with a smooth surface. The cell-wall peptidoglycan contained -diaminopimelic acid. The whole-cell sugars contained ribose, arabinose, and galactose. The predominant menaquinone was MK-8(H). The phospholipid profile included phosphatidylcholine, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylinositol. Based on comparative analysis of genotypic, phenotypic and chemotaxonomic data, strains OC33-EN06 (=TBRC 18349=NBRC 116543), OC33-EN07 (=TBRC 18350=NBRC 116544), and OC33-EN08 (=TBRC 18318=NBRC 116542) represent the type strains of three novel species of the genus for which the names sp. nov., sp. nov., and sp. nov., are proposed.