Tomato Disease Combat and Yield Optimization Using Selenium Nanoparticles: A Sustainable Nano-Agriculture Approach

Tomatoes are a crucial component of the global food system but are susceptible to pests and diseases, such as leaf miner (Tuta absoluta), fungal, and bacterial infections, especially in Pakistan. Synthetic pesticides pose risks to the environment and human health. This study aimed to explore the effectiveness of selenium nanoparticles (SeNPs) in combating these devastating pathogens. SeNPs were synthesized using citrus fruit peel essential oil extracted through hydro-distillation and characterized through X-ray diffraction (XRD) and UV-visible spectrometry. The optimal dosage of SeNPs was determined through bioactivities like antioxidant, antimicrobial, anti-inflammatory, and pesticidal activity before seed priming. UV-visible spectroscopy revealed a surface plasmon resonance at 265 nm. XRD analysis confirmed a crystalline size of 6.4 nm for SeNPs. FTIR analysis confirmed the presence of potential functional groups in the essential oils mediated SeNPs, including alkanes, alkenes, alkyl halides, amines, aromatic compounds, isothiocyanate, alcohols, and carboxylic acids. The synthesized SeNPs demonstrated antimicrobial efficacy against common tomato-infecting pathogens like Fusarium oxysporum, Aspergillus niger, Pseudomonas syringae, and Xanthomonas campestris. Against both bacterial and fungal strains, 10 ppm SeNPs showed a significant diameter of the zone of inhibition, i.e., 39.3 and 28.1 mm against P. syringae and X. campestris, and 26.3 and 39 mm against A. niger and F. oxysporum. SeNPs also exhibited significant pesticidal potential against Tuta absoluta. SeNPs enhanced seed germination percentage up to 94.8%, chlorophyll stability index (84.6%), membrane stabilization index (94%), and reduced root ion leakage (0.183%) at p < 0.001. The present study optimizes the dosage of SeNPs, which shows potential for antimicrobial and pesticidal efficacy, as well as improving seed germination rate, seedling vigor index, chlorophyll stability index, membrane stabilization index, and reducing root ion leakage. These findings offer new insights for sustainable crop management.