اثر چند ترکیب شیمیایی، زیستی و طبیعی در القای مقاومت سیستمیک در گوجه‌فرنگی علیه ویروس پیچیدگی برگ زرد گوجه‌فرنگی (TYLCV) و ویروس موزائیک خیار (CMV)

Viral diseases are responsible for about half of the crop epidemics which cause considerable yeild losses. Genetic resistance, either achieved by the conventional introduction of Mendelian genes or by genetic engineering can be overcome by viruses. At present, there are no known antiviral compounds for effective protection against plant viruses. The potential of inducing systemic resistance in plants with chemical, beneficial microorganisms or natural compounds have already been shown as an alternative or complementary approach against plant viruses. However, for more effective resistance, there is a need for finding of suitable cultivars, effective resistance inducers and optimization of the method. In this study, Tomato yellow leaf curl virus (TYLCV) and Cucumber mosaic virus (CMV) which are two destructive tomato viruses were used as a pathosystem model to assess the efficacy of some natural and chemical resistance inducers to control these viruses in tomato plants. For this purpose, the tomato seedlings were first inoculated with TYLCV and CMV followed by application of seaweed (Ascophilum nodosum) extract, Piriformospora indica fungus, salicylic acid, jasmonic acid and skimmed milk, in single or mixed treatments, in three time-intervals (1 day before inoculation, 1 and 2 days post-inoculation (dpi)). Leaf tissues of inoculated (and treated) plants were sampled at 14 and 35 dpi. Biological indices of the plants were measured and Real-time PCR technique was used to analyse the virus concentration in the treated plants. Total RNA was extracted using Denazist kit and DNA extraction was performed using CTAB method. The results showed that all treatments were effective in reducing the accumulation of both viruses and were consistent with improvement (increase growth) of agronomical traits of thetreated plants compared to control plants (just inoculated with virus). The results of the present study clearly showed that skimmed milk and salicylic acid were the most effective treatments against CMV and jasmonic acid and algae A. nodosum were the most effective treatments against TYLCV.