القاء مقاومت در گوجه‌فرنگی آلوده با Clavibacter michiganensis subsp. michiganensis با سدیم نیترو پروساید

Tomato (Solanum lycopersicum L.) is one of the widely used vegetables cultivated worldwide. Tomato production and consumption are constantly increasing due to its nutritional value and the presence of essential nutrients. Several factors such as cultivar, nutrition, diseases and pests can limit tomato production. Every year, diseases due to less controllability, can lead to significant economic losses to farmers. Tomato bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm) that after entering and multiplying in the plant, colonizes the xylem and causes leaf wilting, canker and eventually plant death. Recently, some messenger molecules have been proposed to manage this disease. Nitric oxide is a key messenger in the response of plants to biotic and abiotic stresses, which has attracted due to its role in the regulation of plant defense genes and increasing the activity of antioxidant enzymes. In this study, the effects of sodium nitroprusside (SNP), as a nitric oxide donor, on the disease severity of bacterial canker of two tomato cultivars (Flat CH and Superchef) were performed. The experiment was conducted as a factorial experiment in a completely randomized design in three replications under greenhouse conditions. The seedlings at the three- to five-leaf stage were transferred to pots containing sterilized perlite, soil and sand. One week after seedlings establishment, a suspension of 108 cfu/ml of the overnight Cmm culture was injected at the branching point of the leaf to the main stem. Foliar spraying with SNP at 0, 50, 100 and 200 µM concentrations was done in three stages (24 hours before pathogen inoculation, 24 and 48 hours after inoculation). The plants were kept under greenhouse conditions with a temperature of 28°C, 16 hours of light and 8 hours of darkness. Three weeks after infection, the evaluation of disease severity was recorded using a numerical scale of zero to five. The results of the variance analysis showed that there was no significant difference between the two cultivars in the disease severity, but there was a significant difference between positive control and the plants treatment with SNP an by increasing the concentration of SNP, the severity of the disease was significantly reduced, so that the application of 100 μM and 200 μM of SNP reduced the disease severity by 82% compared to the positive control (inoculated with Cmm). With regard to the results, the spraying of SNP in the appropriate concentrations can be effective in the control of bacterial canker with inducting systemic resistance in tomato seedlings.