ANTIFUNGAL ACTIVITY OF THE NATURAL PRODUCT AMBRUTICIN VS4 AGAINST ALTERNARIA BRASSICICOLA

Abstract Increased concern for health and environmental hazards associated with the use of fungicides has resulted in the need for greater sustainability in agriculture. Naturally occuring molecules represent an important source of antifungal agents that may be used for the synthesis of new compounds. Myxobacteria are known as excellent and prolific producers of a variety of bioactive secondary metabolites including antibacterial and antifungal compounds. The ambruticin, a natural poliketide originating from the myxobacterium Sorangium cellulosum constitute attractive leads for antifungal drug development. We have analyzed the effect of ambruticin on different Alternaria brassicicola isolates, an economically important seed-borne fungal pathogen of Brassicaceae species. Several isolates, sensitive and highly resistant to dicarboximides (iprodione), were tested for their susceptibility to ambruticin in vitro. In vitro assays investigated the responses of Alternaria brassicicola isolates towards ambruticin VS4 by evaluating the potential toxic effects on mycelial growth. Our results show that the polyketide drug ambruticin VS4 exerted antifungal activity against Alternaria brassicicola, mycelial growth being strongly affected.