Secondary Metabolites from Actinokineospora spp.: Insights into a Sparsely Studied Genus of Actinomycetes

The genus Actinokineospora (family Pseudonocardiaceae) has recently emerged as a prolific source of structurally diverse, biologically active specialized metabolites. Actinokineospora spp. are filamentous actinomycetes isolated from various terrestrial biotopes. The genus is still sparsely represented taxonomically, with only 19 species holding validly published names and genome sequences available for an additional six strains. Nevertheless, Actinokineospora appears to have one of the highest biosynthetic novelty index values among actinomycetes, making it a prime candidate for the discovery of new specialized metabolites. To date, several Actinokineospora strains have shown antimicrobial activity, including Actinokineospora acnipugnans R434T, Actinokineospora alba 03-9939T, Actinokineospora fastidiosa NRRL B-16697T, Actinokineospora riparia C-39162T, Actinokineospora sp. G85, and Actinokineospora sp. PR83; the active compounds from these strains remain to be identified and characterized. By contrast, detailed chemical characterization has been achieved for several producers: Actinokineospora spheciospongiae EG49T (polyketides actinospene and actinosporins; the lasso peptide actinokineosin), Actinokineospora bangkokensis 44EHWT (polyene thailandins), Actinokineospora fastidiosa ATCC 202099 (nocathiacin thiopeptides), Actinokineospora sp. UTMC 2448 (persiathiacin thiopeptides), and Actinokineospora auranticolor DSM 44650T (kineomіcin glycopeptides). Collectively, these findings establish Actinokineospora as a promising yet underexplored genus for antibiotic discovery and biosynthetic engineering. In this review, we summarize current knowledge on Actinokineospora spp. and provide an in-depth account of specialized metabolite production for those compounds whose structures have been elucidated.