Advanced Nanomanagement of Chickpea Wilt through Biosynthesized Metal Oxide Nanoparticles Derived from Syzygium cumini

The burgeoning interest among researchers in nanotechnology stems from the urgent need to devise sustainable alternatives for managing plant diseases and reducing the reliance on environmentally hazardous pesticides. Nanopesticides have emerged as promising solutions to limit the problems associated with the use of chemical fungicides. This study aims to harness the biofabrication potential of Syzygium cumini to synthesize metal oxide nanoparticles (MONPs), iron oxide nanoparticles (IONPs), zinc oxide nanoparticles (ZnO–NPs), and a novel nanocomposite of iron and zinc (Fe–Zn NCs). The fungicidal efficacy of green-synthesized MONPs, both in vitro and in situ, was also evaluated. The MONPs biosynthesized from S. cumini leaf extract were characterized by various microscopic and spectroscopic techniques. The XRD analysis confirmed the crystalline nature of the MONPs, with particle sizes averaging approximately 33.5 nm for IONPs, 22.4 nm for ZnO–NPs, and 20.7 nm for Fe–Zn NCs. SEM revealed distinct morphological features of MONPs that included spherical, pleomorphic, and hexagonal shapes, respectively, for the three NPs. Further characterization of the MONPs was conducted through FTIR, EDX, and Raman analysis. In a pivotal plate assay, the IONPs, ZnO–NPs, and Fe–Zn NCs exhibited a dose-dependent inhibition of the chickpea wilt pathogen, Fusarium oxysporum f. sp. ciceris. Furthermore, the HPLC analysis revealed a substantial decrease in concentrations of three major phenolic compounds, gallic acid, salicylic acid, and shikimic acid, within the pathogen-infected chickpea treated with Fe–Zn NCs. In conclusion, the findings of this study suggest that biosynthesized three MONPs hold the potential to manage wilt infection, concomitantly enhancing chickpea growth.