Effect of water deficit on physiological response, total protein and gene expression of Rab17 in wheat (Triticumaestivum)

Drought is one of the most adverse environmental constraints that impact on plant growth and reduce crop yields.To discus effect of water deficit on molecular and physiological responses, two cultivars of bread wheat (Sardari and Zarin) were selected (based on results accumulated during three years of research described in Heidari et al (1381). The plantswere cultivated in a completely randomized design with three replication in plastic pots containing field soil in growth chambers (30/ 20 °C, 14 h day/ 10 night, 60% R.H).Their response to water stress was performed at the physiological level by determination of relative water content (RWC), chlorophyll, free proline and total proteins content for duration of the drought treatment and subsequent re-watering.All physiological parameters were affected by drought stress. Relative water content of zarin cultivar reduced significantly. The content of chlorophyll a and total chlorophyll in the both cultivars decrease significantly but the change of the content of chlorophyll b in two cultivars wasnt significant. The free proline contents of two cultivars increased significantly and both cultivars could recover to normal condition by re-watering after short term drought. SDS-PAGE electrophoresis of leaf proteins under control and drought treatments showed some up and down regulated proteins.Modification in the expression level of dehydrin (DHN) gene (Rab17) was also analyzed by reverse transcription–polymerase chain reaction (RT-PCR). This gene was expressed slightly in the well water plants of two cultivars, but the gene expression of sardari cultivar increased significantly after long term drought.