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An estimated 35% of the world’s population depends on wheat as their primary crop. One fifth of the world’s wheat is utilized as animal feed, while more than two thirds are used for human consumption. Each year, 17–18% of the world’s wheat is consumed by China and India. In wheat, spot blotch caused by Bipolaris sorokiniana is one of the major diseases which affects the wheat crop growth and yield in warmer and humid regions of the world. The present work was conducted to evaluate the effect of green synthesized silver nanoparticles on the biochemical constituents of wheat crops infected with spot blotch disease. Silver nanoparticles (AgNPs) were synthesized using Mangifera indica leaf extract and their characterization was performed using UV-visible spectroscopy, SEM, XRD, and PSA. Characterization techniques confirm the presence of crystalline, spherical silver nanoparticles with an average size of 52 nm. The effect of green synthesized nanoparticles on antioxidative enzymes, e.g., Superoxide dismutase (SOD), Catalase (CAT), Glutathione Reductase (GR), Peroxidase (POX), and phytochemical precursor enzyme Phenylalanine Ammonia-Lyase (PAL), and on primary and secondary metabolites, e.g., reducing sugar and total phenol, in Bipolaris sorokiniana infected wheat crop were studied. Inoculation of fungal spores was conducted after 40 days of sowing. Subsequently, diseased plants were treated with silver nanoparticles at different concentrations. Elevation in all biochemical constituents was recorded under silver nanoparticle application. The treatment with a concentration of nanoparticles at 50 pp min diseased plants showed the highest resistance towards the pathogen. The efficacy of the green synthesized AgNPs as antibacterial agents was evaluated against multi drug resistant (MDR) bacteria comprising Gram-negative bacteria Escherichia coli (n = 6) and Klebsiella pneumoniae (n = 7) and Gram-positive bacteria Methicillin resistant Staphylococcus aureus (n = 2). The results show promising antibacterial activity with significant inhibition zones observed with the disc diffusion method, thus indicating green synthesized M. indica AgNPs as an active antibacterial agent against MDR pathogens.

Rice is the most important staple food crop feeding more than 50% of the world’s population. Rice blast is the most devastating fungal disease, caused by Magnaporthe oryzae (M. oryzae) which is widespread in rice growing fields causing a significant reduction in the yield. The present study was initiated to evaluate the effect of green synthesized silver nanoparticles (AgNPs) on the biochemical constituents of rice plants infected with blast. AgNPs were synthesized by using Azadirachta indica leaf extract and their characterization was performed using UV-visible spectroscopy, particle size analyser (PSA), scanning electron microscope (SEM), and X-ray diffraction (XRD) which confirmed the presence of crystalline, spherical shaped silver nanoparticles with an average size of 58.9 nm. After 45 days of sowing, artificial inoculation of rice blast disease was performed. After the onset of disease symptoms, the plants were treated with AgNPs with different concentrations. Application of nanoparticles elevated the activity of antioxidative enzymes such as superoxide dismutase, catalase, peroxidase, glutathione reductase, and phenylalanine ammonia-lyase compared to control plants, and total phenol and reducing sugars were also elevated. The outcome of this study showed that an increase in all biochemical constituents was recorded for A. indica silver nanoparticles-treated plants. The highest values were recorded in 30 ppm and 50 ppm AgNPs-treated plants, which showed the highest resistance towards the pathogen. Green synthesized AgNPs can be used in future for disease control in susceptible varieties of rice. The synthesized AgNPs using A. indica leaf extract have shown promising antibacterial activity when tested against 14 multidrug-resistant (MDR) bacteria comprising Gram-negative bacteria Escherichia coli (n = 6) and Klebsiella pneumoniae (n = 7) with a good zone of inhibition diameter, tested with the disc diffusion method. Based on these findings, it appears that A. indica AgNPs have promise as an antibacterial agent effective against MDR pathogens.