Change the P5CS and P5CR genes expression of involved in the biosynthesis of proline and MDA under osmotic stress in the six varieties of wheat (Triticum aestivum L.)

Drought stress is one of the main obstacles in the of crops  production. A factorial experiment in a completely randomized design with four replications, first factor cultivars include Roshan and Kaver (Drought tolerate), Qods and Mahdavi (drought sensitive), Shole and Tabasi (medium resistance to drought) and the second factor was the osmotic stress applied with polyethylene glycol 8000 at three levels of 0,- 5 and -10 bar, Seeds of germinated cultivars were cultured under hogland conditions for 15 days under osmotic stress. In this study, the importance of the expression of P5CS and P5CR genes in relation to proline and MDA accumulation and their physiological role under osmotic stress conditions in six wheat cultivars was investigated. The effect of cultivars on proline accumulation was significant at 5% level .Proline contents of leaf and root of drought tolerant cultivars was -10 times more resistant than drought sensitive cultivars. In order to compare the mean interactions of osmotic stress × cultivars, the highest mean in the cultivars bright (drought tolerant) at osmotic stress level of -10 bars was showed. No significant accumulation of proline was observed in Roshan and Kaver cultivars, which are known as more resistant cultivars. Increasing osmotic stress and increasing MDA concentration were higher in Shole and Tabasi cultivars than other cultivars. By increasing the level of osmotic stress in the cultivars, the relative expression of genes P5CS and P5CR transcription increased. The genes showed at the level of osmotic stress -10 bar in Qods cultivar (sensitive), the gave highest expression in relative transcripts. While The highest relative expression was observed in the osmotic stress level of -5 bar in the Roshan cultivar (drought resistant).