Seaweeds From the Veracruz Rocky Shore (Mexico) as Novel Sources of Bioactive Compounds Against Fusarium Species Pathogenic to Corn (Zea mays).

Corn, the world's most widely cultivated cereal, is severely threatened by Fusarium species, which reduce yields and contaminate crops with mycotoxins harmful to human and animal health. This study evaluated the antifungal activity of 47 crude methanolic extracts from 31 marine macroalgal species collected during rainy and dry seasons along the Veracruz rocky shore (Mexico) against two Fusarium verticillioides strains, one F. proliferatum, and one F. graminearum using the agar dilution method in potato dextrose agar. Spore germination inhibition was assessed by optical microscopy in a Neubauer chamber, and biomass production was quantified spectrophotometrically (600 nm). All assays were performed in triplicate using thiabendazole as positive control. Laurencia obtusa extract from the dry season showed the highest bioactivity, with 26%-75% mycelial growth inhibition, particularly against F. graminearum, followed by Cymopolia barbata (20%-25%). Seventeen extracts reduced Fusarium spore germination. Untargeted metabolomics identified laurinterol, perforene, and 10-hydroxyisolaurene in the active L. obtusa extract as potential antifungal compounds, while molecular docking suggested these sesquiterpenes may interfere with fungal sterol biosynthesis, oxidative balance, and cellular metabolic regulation through multi-target interactions. These results highlight Veracruz marine macroalgae as promising sources of natural antifungal agents for potential application in the biocontrol of Fusarium spp. in corn.