Necrosis-mediated antifungal activity of a Medicago sp. extract with high potential as safe antifungal against phytopathogenic fungi.

AIMS: Fungal infections are a major threat to crop productivity and quality. Synthetic antifungals have been used ensuring high production; however, the environmental negative effects and the induction of resistant strains have been rising concerns about their use. Thus, this work aims to valorize Medicago sp. extracts, as potentially safe and effective antifungals in agriculture.

METHODS AND

RESULTS

The chemical analysis of an ethanolic extract showed mainly flavonoids, with flavones (23.18 ± 0.08 mg g-1) and isoflavones (13.47 ± 0.11 mg g-1) as the main constituents. Dose-dependent cytotoxicity was observed against Saccharomyces cerevisiae, with concomitant loss of plasma membrane integrity, assessed with propidium iodide, and nucleus-cytosolic translocation of the necrosis marker Nhp6A. Extract's cytotoxicity in the mutant strain yca1, affected in an apoptosis-related metacaspase, further suggested a necrotic mode of cell death. Significant in vitro antifungal activity was observed against Botrytis cinerea, Colletotrichum acutatum, Colletotrichum gloeosporioides, Colletotrichum godetiae, Colletotrichum nymphaea, and Diplodia corticola, all phytopathogenic fungi with devastating impact on relevant crops worldwide.

CONCLUSIONS

The results indicate a remarkable antifungal activity by Medicago sp. extract with potential use in the protection of crops by inducing necrosis in fungal phytopathogens.