Deciphering the fertilizing and disease suppression potential of phytofabricated zinc oxide nanoparticles on Brassicajuncea.

Every year 30-50% of crops suffer from fungal and bacterial diseases. Use of various chemically synthesized fungicides and bactericides make the soil environment more toxic and harmful to the plant health. Therefore, there is need to find non-toxic and cost effective alternative against plant pathogen. In recent years, nanotechnology has got attention because of its wide application in different areas of agriculture. Various nanoparticles have been used in agriculture for their fertilizing and antimicrobial potential. Among them zinc oxide nanoparticles (ZnO NPs) have gained the attention of agriculturists as zinc is an essential micronutrient for plants. Antifungal activity of Tb-ZnO NPs (Terminalia bellerica synthesized zinc oxide nanoparticles) against Alternaria brassicae causative agent of blight disease in Brassica juncea has been reported in our previous study. To use Tb-ZnO NPs as nanofungicides and simultaneously as nanofertilizers, the doses of Tb-ZnO NPs beneficial to the Brassica juncea crop is need to be known. Therefore, experiment has been designed to see the protective and curative potential of Tb-ZnO NPs in alluvial and calcareous soil. Biochemical constituents and stress enzymes analysis has shown significant potential of Tb-ZnO NPs at 200 ppm concentration in alleviating the stress caused by A. brassicae by modulating the photosynthetic, biochemical and enzymatic characteristics. Growth parameter analysis confirmed the role of Tb-ZnO NPs in increasing root and shoot length of B. juncea. Yield component such as seed number, seed weight and oil content of B. juncea crop also has been increased. There was one-fold increase in oil content of B. juncea as compared to control. Maximum percent disease control was found to be 70% in alluvial soil (protective method) grown plants. Therefore, present study supports the hypothesis of a relationship between nutrients and disease suppression.

Phytofabricated zinc oxide nanoparticles as a nanofungicide for management of Alternaria blight of Brassica.

Plant pathogens resistant to the commercially available fungicides and bactericides even at higher concentrations are the biggest challenge for the farmers to control the losses due to plant diseases. The antibacterial and antifungal potential of nanomaterials makes them a suitable candidate for the control of plant diseases. Thus, the present study reports the phytofabricated zinc oxide nanoparticles (ZnO Np's) using aqueous plant leaf extract of Terminalia bellerica (Baheda). Characterization of ZnO nanoparticles was done by ultraviolet-visible (UV-Vis) studies, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR) analysis, and transmission electron microscopy (TEM). The presence of pure hexagonal wurtzite crystalline structure of ZnO nanoparticles was confirmed by XRD analysis. The TEM images revealed the spherical to hexagonal shaped ZnO nanoparticles with sizes ranging from 20 to 30 nm. The stabilization of synthesized ZnO nanoparticles through the interactions of terpenoids, steroids, phenylpropanoids, flavonoids, phenolic acids, and enzymes present in the leaf extract was suggested by FTIR analysis. The mechanism of the formation of ZnO nanoparticles using Terminalia bellerica (Baheda) (Tb-ZnO Np's) as a bioactive compound is proposed. These phytofabricated ZnO nanoparticles (Tb-ZnO Np's) have shown significant antifungal potential against Alternaria brassicae the causal agent of Alternaria blight disease/leaf spot disease in Brassica species. The microscopic results confirm the changes in mycelium morphology and reduction in the number of spore germination at 0.2 mg/mL concentration Tb-ZnO Np's.