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

A novel endophytic actinomycete, designated strain A-T 8314(T), was isolated from a wild orchid, Podochilus microphyllus Lindl., collected from Trat Province, Thailand. The taxonomic position of strain A-T 8314(T) 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(T) grew aerobically at an optimum temperature of 20-25 degrees 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 (H-4). The polar lipid profile contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, phosphatidylmonomethylethanolamine, hydroxy-phosphatidylmonomethylethanolamine and hydroxyl phosphatidylethanolamine. The predominant cellular fatty acid was iso-C-16 : 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(T) belonged to the genus Actinomycetospora, and was most closely related to Actinomycetospora chiangmaiensis YIM 0006(T) (98.8 %) and Actinomycetospora corticicola 014-5(T) (98.6 %). The DNA-DNA relatedness values that distinguished A-T 8314(T) 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(T) (= TBRC 5722(T) = NBRC 113235(T)).