بررسی تأثیر تیمار بذر گوجه فرنگی با متیل جاسمونات و حضور سن شکارگر بر بیان ژن‌های مرتبط با دفاع گیاهی

Plants face various environmental stresses during their growth and development, including pests and pathogens. In response to these stresses, plants increase the biosynthesis of various chemical compounds that help them enhance their adaptation and resistance against these factors. One of these chemical compounds is the phytohormone jasmonic acid and its methylated derivative, methyl jasmonate, which play an important role in regulating physiological processes and plant resistance against pests and pathogens. Plant defenses induced by jasmonates include changes in the quantitative and qualitative composition of plant volatile compounds, which can directly affect herbivores and also attract natural enemies of insects. One of these natural enemies is the omnivorous predator Macrolophus pygmaeus. This study aimed to investigate the effect of seed treatment with methyl jasmonate and the presence or absence of the omnivorous predator Macrolophus on the activation of the jasmonic acid pathway in the tomato cultivar Newton. Tomato seeds were soaked for 24 hours in solutions containing 0, 0.1, and 0.2 mM methyl jasmonate and then planted in peat moss-containing pots. At the 30-day stage, the third or fourth leaf of the plants was placed in a mesh cage, and 5 third or fourth instar nymphs of Macrolophus were released in each cage. Mechanical damage simulating tomato leaf miner larvae, Tuta absoluta was also applied 24 hours and 1 hour before leaf sampling. Induced resistance was investigated through DNA extraction and qPCR using the reference gene slActin, as well as the JIP21 and WiPi 2 primers, at the University of Amsterdam. Two reactions were considered for each primer. Since the normality of the variable distribution was rejected, the data analysis was performed using non-parametric tests. Analysis of variance was performed using the Kruskal-Wallis test, and mean comparisons were made using the Mann-Whitney U test (66 Mann-Whitney U tests were performed for each primer). The results showed that the activity of Macrolophus on tomato plants treated with 0.1 mM methyl jasmonate seed treatment led to a significant increase in the expression of genes related to the jasmonic acid pathway (28.93±7.53) compared to plants without seed treatment (3.55 ± 0.60). These results indicate an increase in the effect of induced resistance created by seed treatment in the presence of the Macrolophus. The use of seed priming and increasing the amount and speed of resistance expression in plants when faced with pests can be a simple, integrable with other control methods, and environmentally friendly approach to controlling tomato pests. This approach can help reduce the use of chemical pesticides and increase the sustainability of agricultural systems.