Pre-sowing grain treatment with bio-AgNPs stimulates plant growth and affects redox homeostasis in maize

Joanna Trzcińska-Wencel^1*Natalia Mucha¹Mahendra Rai²Jarosław Tyburski¹Patrycja Golinska^1*

• ¹Nicolaus Copernicus University in Toruń, Toruń, Poland
• ²Sant Gadge Baba Amravati University, Amravati, Maharashtra, India

Introduction: In the pursuit of sustainable development, nanotechnology provides effective solutions for enhancing agricultural productivity. Understanding the nanoparticles (NPs)-plant interaction is essential to identify the potential of NPs for growth stimulation. Therefore, this study aimed to evaluate the effects of silver nanoparticles (AgNPs) from Fusarium solani IOR825 on the growth of Zea mays. Furthermore, the effect of AgNPs on oxidative stress and the antioxidant response was assessed. Methods: AgNPs from F. solani IOR 825 were used for the pre-sowing treatment of maize grains at concentrations of 32, 128 and 512 µgmL-1 . Then, growth parameters and the Ag and total chlorophyll content were analyzed. Hydrogen peroxide (H2O2) and malondialdehyde (MDA) were determined in leaves, roots, stems, and caryopses. The antioxidant system response to the AgNPs treatment was studied by determining total glutathione (GSH+GSSG) and ascorbate (ASC) contents as well as catalase (CAT), superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX) activities. Results: AgNPs were spherical and small (22.97 ± 9.4nm), Zeta potential revealed negative charge, XRD analysis confirmed crystalline structure, FTIR spectrum showed the presence of biomolecules on their surface. The treatment with all tested concentrations of AgNPs resulted in increased dry weight of leaves. Reduced chlorophyll content was observed in plants treated with the highest tested concentration of AgNPs (512 µgmL-1). The treatment of grains with AgNPs decreased H2O2 levels in all organs, except the stem where the oxidant’s level increased. MDA levels were unaffected except for the highest concentration of AgNPs (512 µgmL-1). ASC and total glutathione levels were increased in roots and caryopsis, respectively. The highest impact of AgNPs treatment was determined for SOD activity which decreased in leaves, stem, and caryopsis and increased in roots. CAT activity was decreased in leaves, stems, and roots.Conclusion: The lowest tested concentration of AgNPs (32 µg mL-1) on maize efficiently inhibits maize-borne pathogens, without any negative effect on plant growth and chlorophyll content. However, AgNPs may affect cellular redox systems if higher concentrations are used. The results indicate the potential use of bio-AgNPs in agriculture through a crop-safe approach to eliminate pathogens and increase maize production efficiency.