Investigation of Tomato Spotted Wilt Virus and Fe Interaction on some Physiological Characteristics of Tomato in Greenhouse Conditions

 Tomato, scientifically known as Solanum lycopersicum L., belongs to the Solanaceae family and is susceptible to various diseases, resulting in reduced yield. Among the diseases, the Tomato spotted wilt virus (TSWV), which belongs to the Tospovirus genus and Bunyaviridae family, causes significant damage to tomato crops and other greenhouse plants. Therefore, it is crucial to find ways to increase plant resistance and control viral infections. One effective method is through proper plant nutrition, which can enhance plant resistance by balancing fertilizer consumption and nutrient supply. Iron (Fe) is an essential element for plants and plays a significant role in increasing their tolerance to various stresses. In Order to evaluate the interaction effects of Tomato spotted wilt virus and Fe on some biochemical traits of Mobil and RioGrand tomato cultivars, a study was conducted in Birjand Faculty of Agriculture.

 Experiment in a Random complete design with greenhouse conditions, with 3 replications and 4 treatments Done. Experimental factors include cultivar with two levels (Mobil cultivar and Rio Grand cultivar) and Fe foliar application in the presence of virus with these three (zero, 1.5 and three milliliter of Fe fertilizer per liter of water). First, two varieties of RioGrand and Mobil tomato seeds were prepared and planted in seedlings. Then, in the two-leaf stage, they were transferred to pots filled with sterile soil and kept in greenhouse conditions. After seedling establishment, the first foliar application of Fe fertilizer was done and in the five to seven leaf stage, the virus was inoculated on all leaves. Then, the second stage of fertilizer was applied 10 days after the first fertilizer and finally, after the last stage of foliar application, the samples were transferred to the laboratory. In Order to accurately investigate the effect of Fe on important plant factors, extracts were taken from the samples. Then, the amount of antioxidants, carbohydrates, Flavonoids, Chlorophyll (a, b and total chlorophyll) and phenol was measured. Finally, the final data analysis was performed using SAS statistical software.

 The results showed that the simple effect of cultivar on the amount of phenol and flavonoids was significant at the level of one percent and the highest amount of phenol was recorded in Mobil cultivar and the highest amount of flavonoids was recorded in RioGrand cultivar. The effect of treatments on chlorophyll a, total chlorophyll index and antioxidant enzymes was significant at the level of 1% probability and carbohydrate content at the level of 5% probability. The results showed that feeding Fe at a concentration of 1.5 milliliter had a favorable effect on carbohydrate content and increased its amount in infected plants compared to control plants. This Increase effect may be useful for improving tolerance in a variety of tomatoes. According to the results, an increase in foliar application concentration to 3 milliliters led to a decrease in carbohydrate levels. Mechanical inoculation with a positive sample of the virus resulted in plant contamination. However, virus infection increased carbohydrate and antioxidant enzyme levels in tomatoes. The effect of cultivar on treatment was only significant in the amount of antioxidant enzymes at a one percent probability level, with the Mobil cultivar showing the highest response to virus infection treatment. Therefore, it can be concluded that a concentration of 1.5 milliliters of Fe fertilizer could be effective in increasing carbohydrate levels, as well as utilizing enzymatic and non-enzymatic antioxidant components to prevent viral penetration to some extent and reduce symptoms, particularly in the Mobile cultivar. However, the RioGrand cultivar produced less antioxidant components. Different cultivars of the same plant species have been reported to have varying responses to different types of infections, such as viruses, fungi, and bacteria. These differences are attributed to genetic variations among cultivars, which leads to different resistance mechanisms.

 The final results showed that in the early stages of greenhouse tomato growth, Fe nutrition had an effect on the biochemical properties of the plant and had a positive effect on some traits. In total, Fe fertilizer with a concentration of 1.5 milliliter increased carbohydrates in plants infected with Tomato spotted wilt virus and together with phenol and antioxidants affected the spread of the virus, especially in Mobil cultivar.