Saccharomonospora colocasiae sp. Nov., an actinomycete isolated from the rhizosphere of Colocasia esculenta

A non-Streptomyces actinomycete, designated as strain S265^T, was isolated from rhizosphere collected under an elephant ear plant (Colocasia esculenta) in Bangkok, Thailand. The taxonomic position of this strain was determined by a polyphasic approach. Strain S265^T formed single globose spores on long, branching, aerial hyphae. It produced abundant aerial mycelium with green colour. The cell wall contained meso-diaminopimelic acid, and diagnostic whole-cell sugars were arabinose and galactose. Phosphatidylethanolamine and diphosphatidylglycerol were detected predominantly as polar lipids, whereas mycolic acids were not found. The major menaquinone was MK-9(H₄), and principal cellular fatty acids were C_{15: 1} B, iso-C_{16: 1} H, anteiso-C_{15: 0} and C_{15: 0} 2-OH. The DNA G+C content was 69 mol%. According to phylogenetic analysis, strain S265^T was clustered with Saccharomonospora glauca K62^T (98.1%) and Saccharomonospora viridis DSM 43017^T (97.1%) despite its 16S rRNA gene sequence showing the highest similarity value to that of Saccharomonospora azurea NA-128^T (98.6%). DNA–DNA relatedness values between strain S265^T and the closely related strains were in the range of 7–50%, thus strengthening the evidence derived from the polyphasic study that strain S265^T represents a novel species within the genus Saccharomonospora, for which the name Saccharomonospora colocasiae sp. nov. is proposed. The type strain is S265^T (=TBRC 7235^T=NBRC 112945^T).