ANTIVIRAL ACTIVITY OF Oliveria decumbens Vent. ESSENTIAL OIL ENCAPSULATED IN CHITOSAN NANOPARTICLES TO CONTROL CUCUMBER MOSAIC VIRUS

Plant-derived bioactive compounds have been extensively used as green and environmentally-friendly agents against viral infections in plants. Oliveria decumbens Vent. is a medicinal plant traditionally used in Iranian medicine for the treatment of various infections. Herein, the essential oil (EO) of O. decumbens was extracted and microencapsulated in chitosan nanoparticles to evaluate its activity against the Me isolate of cucumber mosaic virus (CMV-Me). The particles were co-, pre-, and post-treated on leaves of Chenopodium quinoa and Nicotiana tabacum cv. Turkish plants challenged with CMV. To determine the possible physiological and biochemical changes, plant growth indices including fresh and dry weight, height, chlorophyll content, and the activity of defense-related enzymes viz. peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured. The results showed that pre-treatment of the plants with O. decumbens EO encapsulated in chitosan nanoparticles significantly inhibited the development of local lesions in C. quinoa and infection rate in N. tabacum cv. Turkish CMV-challenged plants, respectively. Moreover, the biological indices of pre-treated N. tabacum cv. Turkish plants were found to be more than those of non-treated plants challenged with CMV. Also, a significant increase was observed in POD and PAL content within pre-treated N. tabacum cv. Turkish plants showing the possible antiviral induced resistance mechanism of encapsulated EO from O. decumbens in chitosan nanoparticles. These findings suggest that the reformulation of EO from O. decumbens is a promising biologically active source to control CMV infection in plants.