Effect of the cucumber mosaic virus-Fny infection on the physiological and phytochemical properties of three green basil (Ocimum basilicum L.) cultivars

Green basil (Ocimum basilicum L.) is a medicinal plant widely used in the food, cosmetics, and perfumery industries. Cucumber mosaic virus is one of the most common plant pathogens worldwide. In the present study, the effect of cucumber mosaic virus (strain Fny) infection on the phytochemical and physiological properties of three green basil cultivars under growth chamber conditions (21 ± 2 ° C and 16-hour light/8 hour dark period) was investigated. The plants were mechanically-inoculated in the true two-leaf stage with the virus. Mean comparison of the studied traits showed that the virus significantly reduced photosynthesis, the content of chlorophyll a and b, total chlorophyll, and total carbohydrates in the infected plants. In contrast, the content of total protein, amino acid proline, total phenol, flavonoids, and the percentage of essential oils (w/v) in infected plants was increased. The results of essential oil analysis of three basil cultivars by Gas chromatography and Gas chromatography-mass showed a significant difference in essential oil compounds between control and viral treatments of each cultivar. The compounds Camphor, Carvone, Estragole, Methyl Eugenol, Beta-caryophyllene Alpha bisabolene, and Caryophyllene oxide make up more than 70% of the essential oil content. Results of the present study indicated that viral infection causes physiological and phytochemical changes in virus-infected plants. Increasing and/or decreasing the phytochemical content and some essential oil compounds depends on the interaction of the virus and the basil cultivar and may be in line with the susceptibility or resistance of the cultivars to the virus infection.