Production and characterization of chitosan nanoparticles extracted from Pinus roxburghii needles enhances disease protection against citrus canker

During recent years, nanotechnology has emerged as a promising technology to combat plant diseases.. This present research aimed to synthesize chitosan coated zinc oxide nanoparticles from Pinus roxburghii needles to mitigate the canker disease. Freeze drying and microwave-assisted methods were applied for encapsulation of synthesized nanoparticles. For characterization of nanoparticles UV-Vis, SEM, XRD, FTIR, DLZ, and zeta potential were employed. Results of the present work indicated that the synthesis of nanoparticles has hexagonal Wurtzite structure, while SEM depicted morphology and size. In contrast to the amorphous needles extract and chitosan, the crystalline nature of the nanoparticles is demonstrated by the strong crystalline peaks of XRD between 20 < 2Ө >80° before and after encapsulation. Particle size of 68 nm was determined by DLS that had surface charge of -25.66 mV as determined by zeta potential. Antibacterial activity of ZnO-NPs of Pinus roxburghii extracts with and without encapsulation was evaluated against pathogenic bacteria Xanthomonas citri . Higher antibacterial activity is exhibited by nanoparticles encapsulated through the microwave-assisted method as compared to freeze drying. Antimicrobial activity of needle extract increased by increasing the concentration of chitosan-coated zinc oxide nanoparticles. In conclusion, nanoparticles of Pinus roxburghii have antibacterial effects against Xanthomonas citri , and their activity increases due to encapsulated chitosan for citrus canker disease