Actinomadura rhizosphaerae sp. nov., isolated from rhizosphere soil of the plant Azadirachta indica

A novel actinomycete, strain SDA37 T , belonging to the genus Actinomadura, was isolated from rhizosphere soil collected from Udon Thani Province, Thailand. The taxonomic position of the strain was characterized using a polyphasic approach. Meso-diaminopimelic acid, glucose, ribose, galactose and madurose were detected in cell-wall and whole-cell hydrolysates. The N-acyl type of muramic acid was acetyl. Menaquinones were MK-9(H6), MK-9(H8) and MK-9(H4). The predominant cellular fatty acids were iso-C16 : 0, C16 : 0, 10-methyl C18 : 0 and iso-C14 : 0. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol. blast analysis of the almost-complete 16S rRNA gene sequence showed 98.8 % similarity to Actinomadura oligospora NBRC 104149 T , 98.7 % similarity to Actinomadura gamaensis DSM 100815 T and 97.2 % similarity to Actinomadura rupiterrae KCTC 19559 T . The DNA G+C content was 73.1 mol%. Strain SDA37 T showed low DNA-DNA relatedness (44.3±7.3 to 58.5±8.7 %) to A. oligospora NBRC 104149 T , Actinomadura gamaensis DSM 100815 T and Actinomadura rupiterrae KCTC 19559 T . The new strain could also be distinguished from its closely related strains by the differences in the phenotypic characteristics. The results of taxonomic analysis suggested that strain SDA37 T represented a novel species of the genus Actinomadura for which the name Actinomadura rhizosphaerae sp. nov. is proposed. The type strain is SDA37 T (=KCTC 39965 T =NBRC 112909 T =TISTR 2523 T ).