Turmeric (Curcuma longa L.) rhizome extract mediated silver nanoformulation exhibits enhanced antifungal property against Rhizoctonia solani and boosts innate immunity of rice

Aqueous extract of turmeric rhizomes exhibits antifungal properties against Rhizoctonia solani at higher concentrations. Nanotechnology offers innovative strategies to improve the antifungal potency of the extract. An eco-friendly green synthesis technique was used to formulate silver nanoparticles from turmeric rhizome extract (SNPTs) and characterized by UV-VIS spectrophotometer, dynamic light scattering (DLS), field emission scanning electron microscope (FESEM) and fourier transform infrared spectrometer (FTIR). 100 ppm SNPTs can inhibit the growth of Rhizoctonia solani up to 82% in vitro and 77% in vivo. SNPT-treated fungal mycelia had a 1.5 fold higher reactive oxygen species (ROS) accumulation and a 2-fold decrease in mitochondrial membrane potential (MMP) with elevated cytochrome oxidase 3 (COX 3) and NADH dehydrogenase 5 (NAD 5) (2 and 5.25 fold up-regulation) expression. SNPT nano-primed rice seedlings exhibited enhanced phenylalanine ammonia lyase (PAL), peroxidase (POX), and superoxide dismutase (SOD) activity with up-regulation of phenylalanine ammonia lyase (PAL) and pathogenesis-related protein (PR-protein) gene expression. Nano-primed rice seedlings have a sturdy root system with 2.5-fold more callose accumulation. Taken together, the results suggest SNPT inhibits Rhizoctonia and boosts plant innate immunity simultaneously to acquire resistance against the fungal pathogen.