Fungicidal Activity and In Silico Studies of Triazoles Derived From Glycerol Against Neocosmospora falciformis, A Causal Agent of Guava Tree Decline

Guava tree decline is a complex disease characterized by root rot caused by the soilborne fungus Neocosmospora falciformis. Current management strategies have proven unsatisfactory under field conditions, highlighting the need for research into alternative control methods. This study evaluated the fungicidal activity of seventeen glycerol-derived triazoles against the mycelial growth and sporulation of N. falciformis at concentrations of 1, 10, 100, 500, and 1000 µg/mL. The commercial fungicide tebuconazole was included as a positive control. At 1000 µg/mL, triazole 4l completely inhibited mycelial growth and eliminated N. falciformis spores. Triazoles 4i-4l and 4n-4q also showed satisfactory activity at the highest concentrations in both parameters evaluated. Molecular docking studies investigated the interactions of 1,2,3-triazole derivatives with a modeled lanosterol 14α-demethylase (FsCYP51) from N. falciformis. All derivatives exhibited favorable binding to the enzyme's active site, with binding energies comparable to those of the natural substrate lanosterol and slightly less favorable than that of tebuconazole. These findings suggest that the triazole derivatives effectively prevent lanosterol from accessing the catalytic pocket of FsCYP51, thereby inhibiting its conversion into ergosterol. Notably, the 4l derivative exhibited enhanced activity, likely due to its docked pose superimposed on tebuconazole, underscoring this compound as a candidate for fungicide development.