Investigating the efficacy of bioactive compounds from selected plant extracts against Gibberella fujikuroi species complex associated with damping off disease in sweet corn
Fusarium genera are widespread disease-causing fungi that severely reduce plant productivity and yield quality, particularly in corn. In this study, we investigated the antifungal potential of selected plant extracts against damping-off disease-associated fungi in sweet corn (Zea mays L. saccharata). Fourteen Fusarium isolates were obtained from symptomatic sweet corn plants belonging to five different species, viz. F. fujikuroi, F. proliferatum, F. verticillioides, F. oxysporum, and F. acuminatum. Although all the isolated fungi were pathogenic, F. verticillioides (Fv-A), F. fujikuroi (Ff-A) and F. oxysporum (Fo-W2) were more aggressive showing higher values for infection (%) and infection severity (%) and negatively affected seed germination (%) and other growth variables. Phytochemical analysis for five wildly growing plant species namely; Eruca vesicaria L., Strigosella africana L., Chenopodium album L., Oxalis pes-caprae L. and Ducrosia ismaelis was conducted using GC-MS analysis. The most abundant bioactive compounds in the three selected extracts (E. vesicaria, O. pes-caprae L. and D. ismaelis) were 1-eicosanol, (Z)6,(Z)9-Pentadecadien-1-ol and n-Hexadecanoic acid, and Nonadecane, respectively. Oxacyclotricosan-2-one and D-Homoandrostane from E. vesicaria L.; Vitamin E and Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, methyl ester from O. pes-caprae L. and 7.beta.-(1-hydroxy-1-methylethyl), alpha-gurjunene from D. ismaelis showed extraordinary molecular docking and dynamic properties including high binding free energy, relatively low inhibition constant (pKi), ligand efficiency, and low torsional energy against three fungal enzymes, namely GH10 xylanase, Plant-type chitinase inhibitors, and Sterol 14-alpha Demethylase. Thus, these bioactive compounds can be listed as potential binders of these target proteins and could be used in designing new fungicides.