Fusarium oxysporum induced pathogenesis in ginger (Zingiber officinale) associated with oxidative stress responses, antioxidant defense mechanisms and mycotoxin profiling

Fusarium oxysporum is a destructive soil-borne pathogen responsible for rhizome rot and wilt in ginger ( Zingiber officinale ). In the present study, pathogenic isolates were obtained from infected rhizomes, morphologically identified, and molecularly confirmed by ITS rDNA sequencing. Pathogenicity was validated using in vivo inoculation and detached leaf bioassays. To elucidate disease mechanisms, temporal changes in oxidative stress markers, antioxidant enzyme activities, phenylpropanoid defense enzymes, chlorophyll content, and cell death responses were systematically quantified. Infection resulted in significant accumulation of hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA), accompanied by chlorophyll degradation and membrane damage. Antioxidant enzymes, including superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, showed dynamic induction, indicating activation of host defense systems. Fungal metabolites were extracted, fractionated, and analyzed by GC–MS, revealing fatty acid derivatives and phthalate-associated compounds associated with phytotoxicity. Notably, fraction-specific bioassays demonstrated differential virulence potential, providing functional evidence connecting mycotoxin compositions with oxidative injury in ginger tissues. This integrated biochemical and metabolite-based approach provides new insight into the coordinated role of oxidative stress and fungal secondary metabolites in Fusarium -induced pathogenesis and identifies potential biochemical markers for early disease detection and targeted management strategies.