Morpho-functional characterization, in vitro study, and tripartite interaction assay evaluate the potential of biosynthesized silver nanoparticles to manage Cercospora leaf spot disease in Vigna radiata

We investigated the anti-phytopathogen potential of silver nanoparticles synthesized by the bioreduction of AgNO3in Bacillus subtilisculture supernatant against Cercospora canescens, causing leaf spot disease in Vigna radiata(mungbean). The biosynthesized AgNPs were characterized using UV–visible spectroscopy that showed a broad Surface Plasmon resonance (SPR) peak at 410 nm, dynamic light scattering (DLS) measurement for size distribution and intensity, polydispersity index, and zeta potential for determining their stability. Atomic Force Microscopy determined that they were spherical with an average particle size of 8 nm. In vitro study and tripartite assay under greenhouse conditions were carried out to evaluate the nanoparticles application as a management strategy to control and/ protection from the Cercospora leaf spot disease in mungbean. The inhibitory effect of eight AgNPs concentrations was investigated for in vitro antifungal potential assessment; biosynthesized AgNPs were found to decrease the fungal growth and increase the mycelial inhibition. Their antagonistic effect was also recorded on conidial germination. The conidia under AgNPs exposure showed germination repression. The maximum mycelial inhibition (94.00 ± 0.5) was observed for 800 ppm at 96 h. The greenhouse experimentations revealed the antifungal efficiency of AgNPs against Cercospora Leaf spot disease in mungbean. The 800 ppm AgNPs concentration gave a statistically significant result (46.87 ± 3.74) and proved best in In plantaexperiment with maximum disease reduction. Cercospora leaf spot-induced biochemical alterations were recorded to be reversed towards normal levels after biosynthesized AgNPs application on challenged mungbean plants. Our data unravelled the potential of biosynthesized AgNPs against Cercospora canescenschallenge in mungbean, pointing towards its application in plant disease management.