The influence of iodine nano citrates on juvenile wheat plants at phytopathogenic infection and cooling stress

Abiotic stress factors, including those caused by global climate change, can worsen crop damage from phytopathogenic microorganisms. Iodine, as an inorganic antioxidant in the form of iodine nanoparticles, can serve as an additional element to help maintain the redox balance of cells when used for nano-biofortification of plants. Therefore, our study aimed to evaluate the effect of iodine nanoparticles on changes in the H 2 O 2 pool and leaf pigment composition in the plant-host-phytopathogen system after a sudden, short-term cold snap, along with a preliminary assessment of how treatment with these nanoparticles influences growth parameters of both healthy and infected wheat plants. Notably, a sudden cold snap increased oxidative stress in tissues of young wheat plants affected by phytoplasmas and bacteria, as evidenced by a significant rise in hydrogen peroxide content in leaf tissues and pigment degradation. An increase in H 2 O 2 levels in leaf tissues was also observed following the cooling stress in plants that received pre-sowing treatment with iodine nanoparticles. Iodine treatment may enhance the sensitivity of chloroplasts to oxidative stress and act as an antioxidant, triggering the antioxidant system, thereby helping to stabilize the cellular condition. • A growth-activating effect of I-nanocitrates pre-treatment (1.69 μg/mL) was revealed • Nano I treatment during cooling significantly elevated leaf carotenoid levels. • Nano I application regulates H 2 O 2 content in the leaves at the complex stress of cooling + infection • Application of Nano I during cooling enhances chloroplast structure, compacting thylakoids.