Evaluation of Protein Pattern and Tolerance Mechanism in Two Cultivars of Wheat under Drought Stress in Seedling Stage

In order to assess the protein pattern changes in tolerant and susceptible cultivars of wheat under drought stress in seedling stage and for understanding their mechanism of stress tolerance, two cultivars of spring wheat, including Kavir (as tolerant) and Bahar (as susceptible) were cultured in the growth chamber. Proteome analysis by 2D electrophoresis and staining of gels by Commassie brilliant blue for two cultivars was performed and 20 and 86 protein spots with significant difference between control and drought condition in the Kavir and Bahar cultivars were identified, respectively. Using MALDI-TOF/TOF, 18 and 84 protein spots of them in the Kavir and Bahar was identified. Total of proteins with significant expression changes related to the Kavir were divided into six functional groups, including Calvin cycle (seven protein spots), light reaction of photosynthesis (four spots), nitrogen assimilation and proton transfer (each two spots), the biosynthesis of starch and glycolysis (each one spot) and the unknown proteins (three spots). The number of protein functional groups in the Bahar was more diversity and these proteins were divided into 11 functional groups, while in Bahar as well as Kavir the highest numbers of proteins was related to the Calvin cycle (35 protein spots), light reaction of photosynthesis (22 spots), assimilation of nitrogen (eight spots) and proton transfer (five spots). Generally, the most protein amounts in the Kavir were related to Calvin cycle such as Fructose-bisphosphate aldolase (three spots) and RuBisCO small subunit precursor (two spots), respectively. While more of proteins involved in the Calvin cycle of Bahar cultivar such as RuBisCO activase A proteins (seven spots), fructose 1, 6-biphosphate aldolase (six spots) and catalytic large subunit of RuBisCO (five spots) were. On the other hand, in Bahar, proteins of OEC (12 spots) were the largest of protein groups involved in light reaction of photosynthesis. While in the Kavir, Cytochrome b6-f complex, Chlorophyll a-b binding protein, CYP38 and HCF136 protein under drought stress just one of each apiece were induced. Also in the Kavir and Bahar, the largest of protein groups related to nitrogen assimilation were Glutamine synthetase (GS) enzyme. Generally, these results to identify and better understand of the metabolic pathways, effective proteins and important proteins involved in tolerance and sensitivity of wheat will help.