The role of silver nanoparticles in yellow lupine (Lupinus luteus L.) defense response to Fusarium oxysporum f.sp. lupini

This study presents the influence of silver nanoparticles (AgNPs) on the growth of yellow lupine (Lupinus luteus L.cv. Diament and Lupinus luteus L.cv. Mister), and some metabolic reactions triggered by AgNPs during the seed germination stage and development of the seedling. Also, the role of AgNPs in defense mechanisms of the above of yellow lupine varieties against hemibiotrofic patogen Fusarium oxysporum f.sp. lupini. AgNPs enhanced the growth of yellow lupine seedlings, particularly root length and fresh biomass. Furthermore, AgNPs triggered defense-related phytohormones, such as abscisic acid (ABA), jasmonates (JA/MeJA), and salicylic acid (SA), which were involved in defense response of yellow lupine against F. oxysporum infection. The application of AgNPs significantly enhanced the growth of yellow lupine seedlings, increasing root length by over 400% and fresh biomass by 183% compared to the control. Moreover, AgNPs also significantly triggered an important defense-related phytohormone ABA, which increased by 103- and 38-times in Diament and Mister varieties, respectively. AgNPs influenced soluble sugar levels, such as sucrose and fructose, in yellow lupine, which may be related to defense mechanisms. The treatment with AgNPs induced a hormetic effect, where the roots of seedlings exhibited increased growth and defense responses at low concentrations. The level of gibberellic acid (GA) increased by 556% and 297% in AgNP-pretreated embryo axes of Diament and Mister varieties, respectively. Sugar levels, such as sucrose and fructose, were also influenced by AgNPs. In Diament variety, sucrose and fructose levels increased by 60% and 146%, respectively. However, F. oxysporum infection caused a strong decline in sugar levels. Overall, the study suggests that AgNPs can be used to enhance plant growth and defense against pathogens.