Antifungal profile and mechanism of bioinspired nanoscale magnesium against the agriculturally important pathogen Fusarium oxysporum f. sp. niveum

Abstract

Fusarium wilt, caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. niveum (Fon), threatens global watermelon production. Conventional fungicides have limitations in efficacy and environmental impact, prompting the search for alternative disease management strategies. In this study, we investigated the potential of biogenic magnesium nanoparticles (MgNPs), extracellulary-synthesized using Bacillus marisflavi NOT10 culture supernatant, as an effective alternative for managing Fusarium wilt. Here, we elucidated the molecular action mechanism underlying the antifungal activity of MgNPs against Fon. Through a series of greenhouse and in vitro assays, we demonstrated that biogenic MgNPs effectively inhibited Fon growth, development, and pathogenicity. Our results demonstrated that MgNPs effectively suppressed watermelon Fusarium wilt by ∼78% and invasive in planta fungal growth by targeting specific Peroxin (PEX) genes, including FonPEX2, FonPEX8, and FonPEX10, leading to their downregulation. This molecular targeting might resulted in cell wall damage, reduced conidiation, impaired conidial germination, and compromised hyphal morphology in Fon. Notably, ΔFonPex2, ΔFonPex8, and ΔFonPex10 deletion mutants showed enhanced sensitivity to biogenic MgNPs than the WT, further validating their involvement in regulating response to MgNPs in Fon. Overall, our findings provide novel insights into the molecular mechanisms underlying the antifungal activity of MgNPs and contribute to the development of innovative NP-based solutions for plant disease control in agriculture.