Biogenic iron oxide nanoparticles synthesized using Trichoderma spp.: A sustainable approach for fusarium wilt management in tomato.

Fusarium wilt caused by Fusarium oxysporum poses a significant threat to tomato cultivation worldwide and requiring the development of sustainable and effective control measures. This study explored the potential of biologically synthesized iron oxide nanoparticles (IONPs) as an eco-friendly alternative to conventional fungicides and evaluated their antifungal efficacy along with plant health impact. The IONPs were synthesized using Trichoderma spp. metabolites and characterized using multiple analytical techniques. DLS and XRD analyses confirmed a uniform size distribution (80 nm hydrodynamic size and 16.83 nm crystallite size). SEM imaging showed agglomerated particles ranging from 30 to 50 nm, while EDX confirmed Fe and O as the primary elements. FTIR spectroscopy indicated the presence of protein capping agents and Fe-O bonds. In vitro studies demonstrated significant antifungal activity with 76.19% growth inhibition against F. oxysporum compared to commercial carbendazim (17.86%). Greenhouse experiments showed dose-dependent effects with 100 ppm IONPs treatment resulted in remarkable improvements in plant growth parameters: 143.1% increase in shoot length, 178.8% in root length, and 505.9% in wet weight. Disease incidence was reduced by 89.8% at a concentration of 100 ppm, whereas the disease severity index decreased by 60%. Plant physiological analysis revealed an enhanced chlorophyll content (237.3% increase at 100 ppm) and modulated stress enzyme (superoxide dismutase and peroxidase) activity. The soil dehydrogenase activity improved by 170% after treatment with 100 ppm. Furthermore, toxicity prediction indicated a low toxicity potential (LD50: 5000 mg/kg, class 4), supporting it's safe agricultural applications. This study highlights biosynthesized IONPs as an eco-friendly alternative for Fusarium wilt management, offering potential in sustainable agriculture.