Microbe mediated synthesis of iron oxide nanoparticles for the management of biotic and abiotic stress

Abstract

Agricultural productivity faces unprecedented challenges from escalating abiotic and biotic stresses that significantly reduce crop yields and threaten global food security. Conventional mitigation strategies often proved to be inadequate or environmentally unsustainable; therefore, necessitating the development of innovative and eco-friendly solutions. This study investigated the synthesis and application of iron oxide nanoparticles (IONPs) via microbial routes as multifunctional stress-mitigating agents for both abiotic and biotic challenges for maintaining environmental sustainability. Computational toxicity assessment using ProTox-II analysis revealed encouraging safety profiles for the synthesized IONPs and demonstrating their potential suitability for agricultural applications. IONPs were successfully synthesized using various bacterial and fungal metabolites, and comprehensive characterization was conducted using dynamic light scattering, UV-visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis. The efficacy of the biogenically synthesized IONPs was evaluated against multiple abiotic stresses salinity, drought, cobalt and lead toxicity in rice plants and biotic stresses Fusarium oxysporum, Alternaria alternata, and Ralstonia solanacearum in tomato plants. The results demonstrated the significant ameliorative effects of IONPs on plant physiological parameters such as growth characteristics, chlorophyll content, antioxidant enzyme activity and reduced osmotic stress indicators. Furthermore, IONPs exhibited substantial antimicrobial activity against the tested phytopathogens through multiple mechanisms including the generation of reactive oxygen species (ROS) and membrane disruption. The soil health parameters showed remarkable improvement following IONPs application with enhanced dehydrogenase activity, organic carbon content, and macronutrient availability.