Biofabrication of silver nanoparticles using Thevetia peruviana fruit extract for effective management of fungal pathogens and growth enhancement in solanaceous crops

The widespread use of synthetic fungicides and antibiotics in agriculture has led to significant challenges, including environmental pollution, degradation of soil fertility, and the emergence of resistant pathogens. These issues require the development of eco-friendly and sustainable alternatives for plant disease management. Hence, this research explores the production and characteristics of Thevetia peruviana fruit extract-mediated silver nanoparticles (TF-AgNPs) and their potential uses in managing plant diseases. TF-AgNPs were synthesized using a simple green method and characterized extensively by UV-Vis spectrometry, XRD, FTIR, TEM, zeta potential, EDX, DLS, and TGA analyses. The nanoparticles exhibited crystalline nature with face-centered cubic structure, as confirmed by XRD with a typical particle size of 53.2 nm as determined by TEM and DLS. Morphological analysis revealed spherical and oval-shaped TF-AgNPs with slight agglomeration and polydispersity (size range: 19–74 nm). TF-AgNPs were tested for their antibacterial activity against a variety of pathogenic bacteria, which demonstrated strong inhibitory effects. Moreover, TF-AgNPs showed potent antifungal activity against Alternaria solani and Fusarium solani . Additionally, TF-AgNPs improved germination of seeds and seedling vigor in tomatoes and chilies under in vitro conditions. Under greenhouse conditions, TF-AgNPs mitigated disease incidence and severity in tomato and chili plants infected with A. solani and F. solani , leading to improved root and shoot lengths, etc. Furthermore, biochemical defense responses were quantified, showing elevated levels of defense enzymes, including β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and peroxidase (POX), in TF-AgNPs-treated plants compared to controls. Overall, these findings highlight the possible use of TF-AgNPs as antimicrobials and for plant disease management and growth promotion after extensive field trials.