Antifungal Potential of Diaporthe sp. Endophytes from Antillean Avocado Against Fusarium spp.: From Organic Extracts to In Silico Chitin Synthase Inhibition

Fungal endophytes have emerged as a promising source of bioactive compounds with potent antifungal properties for plant disease management. This study aimed to isolate and characterize fungal endophytes from Antillean avocado (Persea americana var. ameri-cana) trees in the Colombian Caribbean, capable of producing bio-fungicide metabolites against Fusarium solani and Fusarium equiseti. For this, dual-culture assays, liquid-state fermentation of endophytic isolates, and metabolite extractions were conducted. From 88 isolates recovered from leaves and roots, those classified within the Diaporthe genus ex-hibited the most significant antifungal activity. Their organic extracts displayed median inhibitory concentrations (IC₅₀) approaching 200 μg/mL. To investigate the mechanism of action, in silico studies targeting Chitin Synthase (CS) were performed, including homolo-gy models of the pathogens' CS generated using Robetta, followed by molecular docking with Vina, and interaction fingerprint similarity analysis of 15 antifungal metabolites produced by Diaporthe species using PROLIF. A consensus scoring strategy identified di-aporxanthone A (12) and diaporxanthone B (13) as the most promising candidates, achieving scores up to 0.73 against F. equiseti, comparable to the control Nikkomycin Z (0.82). These results suggest that Antillean avocado endophytes produce bioactive metab-olites that may inhibit fungal cell wall synthesis, offering a sustainable alternative for disease management.