One novel actinobacterial isolate, designated strain NEAU-G17T, was isolated from muddy soil collected from a riverbank in Chad and characterised using polyphasic approach. Morphological and chemotaxonomic characteristics of this strain coincided with those of the genus Actinomadura. The 16S rRNA gene sequence analysis showed that strain NEAU-G17T was most closely related to Actinomadura oligospora JCM 10648T (98.7 %) and Actinomadura gamaensis NEAU-Gz5T (98.6 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-G17T formed a cluster with Actinomadura oligospora JCM 10648T, Actinomadura gamaensis NEAU-Gz5T and Actinomadura rupiterrae CS5-AC15T (96.4 %). However, the combination of DNA-DNA hybridisation values and some phenotypic characteristics allowed the isolate to be differentiated from their most closely related species. The major menaquinones were identified as MK-9(H4), MK-9(H6) and MK-9(H8). Their polar lipid profile was found to contain diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, an unidentified phospholipid and an unidentified lipid. The major fatty acids were identified as C16 : 0, iso-C16 : 0 and C18 : 1 ω9c. Therefore, it is proposed that strain NEAU-G17T should be classified as representative of a novel species of the genus Actinomadura, for which the name Actinomadura logoneensis sp. nov. is proposed. The type strains is NEAU-G17T (=CGMCC 4.7411T=DSM 105122T).
Keywords: 16S rRNA gene; Actinomadura logoneensis sp. nov.; Polyphasic analysis.