Insights into the dynamics of biochemical profile and relative gene expression of cucumber fruits associated with Fusarium spoilage

The present study investigates the impact of five Fusarium strains viz., two F. verticillioides, two F. proliferatum and one F. concentricum that were isolated from infected cucumber fruits and identified by morphological and molecular analysis on the postharvest spoilage of cucumber. The pathogenicity results revealed all these isolates as virulent accentuating F. concentricum as a highly virulent causing rapid and whole spoilage (100%) of cucumber. Biochemical analysis showed a significant increase in the level of various antioxidants (POD, SOD, CAT, GPX, APX), cell wall-modifying enzymes (PG, PME), and oxidative stressors viz., MDA and H₂O₂. Contrary, Fusarium infection particularly F. concentricum inoculated cucumber demonstrated significant reduction in protein (0.23 mgg⁻¹), starch (0.21gkg⁻¹), cellulose (0.59 gkg⁻¹), and key antioxidants viz., AsA (13.27 µmolg⁻¹) and GSH (nmolg⁻¹) as compared to other Fusarium strains followed by control (2.79 mgg⁻¹, 2.16 gkg⁻¹, 4.87 gkg⁻¹, 32.87 µmolg⁻¹ (AsA), 19.15 nmolg⁻¹ (GSH), respectively. Comparatively, F. concentricum inoculated cucumber fruits exhibited higher electrolyte leakage (97.09%) than other strains over control (20.18%). The study emphasizes that Fusarium species pose a significant threat during cucumber storage, particularly F. concentricum, which accelerates hasty spoilage thereby disturbing the biochemical and defense-related enzymes. Taking into account the rigorous effect of this devastating pathogen-effective management strategies like optimized temperature during storage and/or pre-treatment with essential oils, beneficial microorganisms, or suitable bio-coating with chitosan could be an effective tool to hinder the spread of this pathogen. Harnessing these approaches would mitigate the spread and postharvest losses of this devastating pathogen.