تأثیر اسانس آویشن دنایی و اسید سالیسیلیک بر بیان ژن‌های دفاعی گیاه در خیار آلوده با بیمارگر Verticillium dahlia

Greenhouse cucumber is attacked by many pests and pathogens. In recent years, Verticillium wilt disease of cucumber has spread in a large number of greenhouses in Varamin region, so that the damage caused by it in some greenhouses has been estimated up to 50%. Fungus development occurs in cool and moist spring conditions, but foliage wilting does not occur as long as the weather is sunny and warm and the plant is not under stress. The most common way to control this disease is the use of fungicides, but the repeated use of fungicide compounds has adverse side effects for humans and the environment and also leads to the development of resistance in the pathogenic population. Therefore, in this research, the effect of Thymus daenensis essential oil and salicylic acid, which induces resistance in cucumber plants, in interaction with V. dahlia pathogen on the expression of defense genes in the plant using Real Time PCR method. The genes studied in this research were peroxidase, polyphenol oxidase and catalase. This research was carried out in a period of twenty days after the cucumber plant was infected with the fungal pathogen and inoculated with salicylic acid and thyme essential oil. The treatments included plants treated with distilled water, plants treated with thyme essential oil, plants treated with salicylic acid, plants treated with thyme essential oil and salicylic acid, plants treated with thyme essential oil, salicylic acid and pathogen. The expression level of all three genes, in all treatments, increased from the fourth day of sampling and reached its highest value on the twelfth day for all three genes. In the case of all three genes, the expression level showed the highest value in the treatment of the combined use of the three agents of Denai thyme essential oil, salicylic acid, and pathogen in all sampling days. The expression levels of peroxidase, polyphenol oxidase and catalase genes in this treatment, on the second day, were 280, 176 and 365 times their expression levels in the control treatment (inoculated with distilled water), respectively. After the 12th day, the expression level of all three genes decreased, and until the 20th day, this trend was decreasing. After the mentioned treatment, the treatment using essential oil and salicylic acid showed the highest expression of defense genes (peroxidase, polyphenol oxidase, and catalase), and in the next order, salicylic acid treatments alone and thyme essential oil treatment alone were ranked respectively. The results of this research showed that the essential oil of thyme and salicylic acid act as inducers of defense genes and have the ability to be used in plant disease management programs.