Evaluation of the effect of salicylic acid on altering the expression of some resistance genes against Fusarium wilt in tomatoes

In order to control Fusarium oxysporum, responsible for fusarium wilt disease, in tomatoes, salicylic acid was used as a resistance inducer. Tomato root was inoculated with pathogen suspension and sprayed with 0.1 mM salicylic acid. Leaf samples were prepared at 0, 1, 3, 5, 7 and 14 days after foliar application to evaluate the expression of genes encoding catalase (CAT), peroxidase (POX), superoxide dismutase (SOD) and pathogenesis related proteins (PR1 and PR10) using RT-qPCR. The results showed that the expression of CAT and SOD genes as antioxidant enzymes and effective against negative consequences of disease in infected plants increased sharply compared to the control and the upward trend of expression of these genes continued until the fourteenth day after foliar application, but the POX gene increased until the fifth day and then decreased. This indicates that the catalase gene has a more effective role in disease resistance than peroxidase. PR genes in both healthy and diseased plants increased over 14 days in response to salicylic acid treatment, which was greater for diseased plants than for healthy plants and indicates the induced role of salicylic acid in Fusarium wilt resistance. Therefore, salicylic acid treatment can be used as an ideal candidate to create resistance and prevent damage to the tomato crop.