Lecanicillium aphanocladii–derived copper oxide nanoparticles as a green nano-fungicide enhancing molecular and antioxidant defense against fusarium wilt in potato

Abstract Background Utilizing fungal metabolic processes for the eco-friendly synthesis of nanomaterials has arisen as a sustainable substitute for chemical manufacturing. To the best of our knowledge, this is the first report describing the mycosynthesis of bioactive CuONPs using Lecanicillium aphanocladii and evaluating their efficacy against potato Fusarium wilt. Results Herein, CuONPs were mycosynthesized utilizing the cell-free filtrate of L. aphanocladii AUMC-16936, acting as a bio-reductant and capping agent. Characterization of mycosynthesized CuONPs confirmed the precise composition of the rod-shaped with a mean particle size of 15.24 ± 4.19 nm. The biogenic CuONPs demonstrated potent antifungal activity in vitro against Fusarium oxysporum, with 100 ppm identified as the optimal inhibitory concentration. In vivo trials, Foliar application of the mycosynthesized CuONPs (100 ppm) proved superior to soil watering, significantly mitigating Fusarium wilt severity. The treatment triggered a systemic defense response, evidenced by the upregulation of antioxidant enzymes, along with non-enzymatic indicators, leading to a marked reduction in oxidative stress markers (H2O2, MDA). Moreover, elevated expression levels of several regulatory defense genes, such as PR-1b, IbBBx24, and CHI, were noted in all plants that have been treated in comparison to infected ones. Conclusions The study presents a novel and interdisciplinary approach combining mycology, nanotechnology, and plant pathology to develop an eco-friendly strategy against potato Fusarium wilt.