Synergistic Action of Biosynthesized Silver Nanoparticles and Culture Supernatant of against the Soft Rot Pathogen .

Nanomaterials are increasingly being used for crop growth, especially as a new paradigm for plant disease management. Among the other nanomaterials, silver nanoparticles (AgNPs) draw a great deal of attention because of their unique features and multiple usages. Rapid expansion in nanotechnology and utilization of AgNPs in a large range of areas resulted in the substantial release of these nanoparticles into the soil and water environment, causing concern for the safety of ecosystems and phytosanitary. In an attempt to find an effective control measure for sweet potato soft rot disease, the pathogen was exposed to AgNPs, the cell-free culture supernatant (CFCS) of alone, and both in combination. AgNPs were synthesized using CFCS of strain A3. The green synthesized AgNPs exhibited a characteristic surface plasmon resonance peak at 410-420 nm. Electron microscopy and X-ray diffraction spectroscopy determined the nanocrystalline nature and 20-100 nm diameters of AgNPs. Release of metal Ag ion from biosynthesized AgNPs increases with time. AgNPs and CFCS of alone exhibited antibacterial activity against the growth, biofilm formation, swimming motility, and virulence of strain A3. The antibacterial activities elevated with the elevation in AgNPs and CFCS concentration. Similar antibacterial activities against were obtained with AgNPs at 50 µg·mL, 50% CFCS alone, and the combination of AgNPs at 12 µg·mL and 12% CFCS of . In planta experiments indicated that all the treatments reduced infection and increased plant growth. These findings suggest that AgNPs along with CFCS of can be applied to minimize this bacterial disease by controlling pathogen-contaminated sweet potato tuber with minimum Ag nano-pollutant in the environment.