PROTEOMIC EVALUATION OF TRITICUM BOEOTICUM RESPONSE TO SALINITY STRESS

Abstract

Wild wheat (Triticum boeoticum) has been an essential agricultural crop and primary food source since ancient times. With the growing population and increasing demand for agricultural products, particularly wheat, boosting wheat production is crucial. Due to the limited arable land, enhancing wheat production requires improving yield per unit area, which can be achieved through advanced agricultural practices and developing varieties resistant to diseases and environmental stresses such as salinity. Salinity stress is a significant non-biotic stress that adversely affects the quantity and quality of agricultural products, with 20% of the world's irrigated agricultural lands affected. Understanding the molecular mechanisms of salinity stress tolerance in wheat is therefore vital. In 2017, an experimental study was conducted in a controlled growth chamber at the Faculty of Agriculture, University of Tehran. Five populations of wild wheat (Triticum boeoticum) were evaluated using a pot culture. The study was designed as a factorial experiment in a completely randomized design with three replications in a greenhouse. Factors included genotype (5 genotypes) and salinity (0 and 150 mM). Seeds were sown in plastic pots, and after two weeks, at the beginning of the three-leaf stage, salinity stress was applied using 150 mM NaCl. Two weeks after salinity stress application, seedlings were harvested, and traits such as shoot and root length, fresh and dry weight of shoots, total protein, and chlorophyll and carotenoid content in leaf tissues were measured. Results showed that population B4 had the highest values for all traits except shoot height. The mean effect of population on traits such as shoot length, root length, chlorophyll a, and b indicated that population A1, followed by B4, had the highest values for shoot height. The lowest values for shoot length, root length, chlorophyll a, and b were observed in populations B3, C5, B3, and A10, respectively. The interaction effect of population and salinity on traits such as chlorophyll a, b, and total carotenoids was not significant. This might be due to the higher tolerance of wild wheat populations to salinity stress over the two-week stress application period. The mean interaction effect of population and salinity on total protein showed that population B4 had the highest value under salinity stress, while population A1 had the lowest value under salinity stress. This suggests that population B4 responds to salinity stress by altering protein expression to tolerate these conditions.Proteomic analysis of genotype B4 using two-dimensional electrophoresis identified 10 protein spots with significant expression changes, with 9 spots showing increased expression and 1 spot showing decreased expression. The identified proteins were‌ categorized into various biological function groups, including energy metabolism, translation, protein processing and degradation, photosynthesis, defense, and resistance mechanisms.