Actinomycetospora endophytica sp. nov., isolated from wild orchid (Podochilus microphyllus Lindl.) in Thailand.

A novel endophytic actinomycete, designated strain A-T 8314, was isolated from a wild orchid, Podochilus microphyllus Lindl., collected from Trat Province, Thailand. The taxonomic position of strain A-T 8314 was established using a combination of genotypic and phenotypic analyses. The isolate was a Gram-positive bacterium that developed bud-like spore chains. Strain A-T 8314 grew aerobically at an optimum temperature of 20-25 °C and an optimal pH 6.0. The cell wall contained meso-diaminopimelic acid, and the whole-cell sugars were ribose, arabinose and galactose. The predominant menaquinone was MK-8 (H4). The polar lipid profile contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, phosphatidylmonomethylethanolamine, hydroxy-phosphatidylmonomethylethanolamine and hydroxyl phosphatidylethanolamine. The predominant cellular fatty acid was iso-C16 : 0. The DNA G+C content of the genomic DNA was 73.2±0.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain A-T 8314 belonged to the genus Actinomycetospora, and was most closely related to Actinomycetospora chiangmaiensis YIM 0006 (98.8 %) and Actinomycetosporacorticicola 014-5 (98.6 %). The DNA-DNA relatedness values that distinguished A-T 8314 from its closest species were below 70 %. Following an evaluation of phenotypic, chemotaxonomic and genotypic studies, it was concluded that the new isolate represents as a novel species, for which the name Actinomycetospora endophytica sp. nov is proposed. The type strain is A-T 8314 (=TBRC 5722=NBRC 113235).