Micromonospora azadirachtae sp. nov., isolated from roots of Azadirachta indica A. Juss. var. siamensis Valeton

A Gram-stain positive actinomycete, strain AZ1-19(T), isolated from roots of Azadirachta indica A. Juss. var. siamensis Valeton, collected from Chachoengsao province, Thailand, was characterised taxonomically by using a polyphasic approach. Strain AZ1-19(T) was found to have characteristics consistent with those of members of the genus Micromonospora. The cell wall peptidoglycan of the strain was found to contain meso-diaminopimelic acid. The predominant phospholipids were identified as diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The characteristic whole-cell sugars were identified as glucose, xylose, galactose and mannose. The major menaquinones were found to be MK-9(H-6), MK-10(H-6) and MK-10(H-8), and the major cellular fatty acids were identified as iso-C-16:0, iso-C-15:0, anteiso-C-15:0 and anteiso-C-17:0. Comparative analysis of 16S rRNA gene sequences revealed that strain AZ1-19(T) is closely related to Micromonospora costi CS1-12(T) (98.75% similarity), Micromonospora avicenniae 268506(T) (98.75%), Micromonospora haikouensis 232617(T) (98.68%) and Micromonospora siamensis TT2-4(T) (98.61%), whilst the corresponding phylogenetic analysis based on partial gyrase subunit B (gyrB) gene sequences indicated that strain AZ1-19(T) forms a clade with M. avicenniae 268506(T) with a high bootstrap value. The DNA G+C content was determined to be 69.8mol%. Moreover, a combination of DNA-DNA relatedness values and some phenotypic and chemotaxonomic properties indicated that the strain could be distinguished from closely related species. Therefore, it is considered that strain AZ1-19(T) represents a novel Micromonospora species for which the name Micromonospora azadirachtae sp. nov. is proposed. The type strain is AZ1-19(T) (=KCTC 39941(T)=NBRC 112784(T)=JCM 32148(T)=TISTR 2559(T)).