Surface-Functionalized Silver Nanoparticles Boost Oxidative Stress and Prime Potatoes Against Phytopathogens

The study investigates the use of silver nanoparticles (AgNPs) in agriculture, focusing on their potential to enhance the immune response of potato (<i>Solanum tuberosum</i> L.) plants against phytopathogenic attacks. The research highlights how AgNPs, stabilized by biologically active polymers polyhexamethylene biguanide and tallow amphopolycarboxyglycinate, can induce oxidative stress. Triple foliar application of 0.1-9.0 g/ha silver nanoparticles at the budding and later stages demonstrated significant efficacy in suppressing diseases caused by <i>Phytophthora infestans</i> and <i>Alternaria solani</i> (over 60%). This effect was linked to the increased activity of peroxidase-over 30-50%-and the decreased catalase activity, indicative of a well-coordinated oxidative stress response to the invasion of <i>P. infestans</i> and <i>A. solani</i>. The results suggest that AgNPs in low concentrations can prime the plant's innate immune system, enhancing its resistance without detrimental effects on growth parameters, thus contributing to the improved crop yield. These findings underscore the potential of AgNPs not as traditional biocides, but as intelligent elicitors of plant-induced resistance, positioning them as next-generation tools for sustainable crop protection and yield optimization, which can be applied at extremely low doses (less than 10 g/ha of active substance).