Assessment of inhibitory potentiality of natural compounds against worrisome rice blast fungus.

Abstract

Rice blast, a severe fungal disease, is a substantial threat to global food security, particularly in rice-oriented areas. The Magnaporthe oryzae fungus is increasingly resistant and fast developing in nature. However, chemical fungicides are not only detrimental to the environment but eventually also lose their efficiency. To Tackle this issue, we used an in silico based strategy to identify plant metabolites as bio-fungicides to combat rice blast. Therefore, we screened a total of 56 antifungal natural compounds for the ability to inhibit fungal development through the targeted inhibition of essential proteins in the rice blast pathogen. Molecular docking analysis identified curcumin, myricetin, sterigmatocystin, and versicolorin B as promising candidates with superior binding affinities compared to conventional fungicides like strobilurin, azoxystrobin, and tricyclazole. Notably, myricetin showed the docking score for the SD protein of -233.20, whereas versicolorin B demonstrated the highest binding affinity for the SD protein of -234.23. Among the control fungicides, azoxystrobin displayed the lowest docking score of -177.53. The docked complexes were found to be stable based on molecular dynamics simulations results; the binding free energies of SD-Versicolorin B (-156.018 ± 24.881 kJ/mol) and SD-Myricetin (-137.526 ± 19.977 kJ/mol) complexes were also found to be favorable. Taking everything considered, these naturally occurring substances showed strong fungicidal effects against rice blast causative agent while remaining non-toxic, providing encouraging substitutes for traditional fungicides. In conclusion, these non-toxic natural compounds exhibited strong fungicidal action against rice blast, suggesting promising alternatives to conventional fungicides.