Identification and characterization of antifungal molecules of marine origin in the Cies Islands

Abstract

The increasing global demand for food and the necessity to ensure food security are significantly challenged by fungal pathogens in crops. These pathogens not only diminish agricultural productivity but also produce mycotoxins harmful to human and animal health. The dependence on synthetic fungicides has resulted in environmental issues and the emergence of resistant strains, underscoring the need for alternative solutions. In this context, the exploration of bioactive compounds from marine sources presents a promising pathway for discovering new, sustainable, and effective natural antifungal agents. This research involved bioprospecting marine samples from the Cies Islands, isolating microorganisms, and generating a collection of organic extracts. The antifungal activity against the phytopathogen Botrytis cinerea of both these extracts and the centrifuged broth was analyzed, which made it possible to detect hydrophilic secondary metabolites not captured in their entirety in the extracts. The results of the antifungal assays revealed that 64 out of 1726 extracts demonstrated significant antifungal activity, and 24 out of 267 centrifuged broths showed similar potential. Chemical dereplication through high-performance liquid chromatography (HPLC) identified 50 different compounds with a wide diversity of secondary metabolites, including some known compounds such as ergosterol, maculosin, and FKI0076A. Finally molecular taxonomic identification of several active strains was carried out by DNA sequencing. The results underscore the potential of marine microorganisms as promising reservoirs of bioactive molecules. This research highlights the viability of natural marine compounds as antifungal agents and reinforces the importance of exploring marine environments as a source of new natural antifungal agents that could contribute significantly to global sustainability and food security.