ROLE OF SIGNAL TRANSDUCTION IN REGULATION OF GENE EXPRESSION OF DROUGHT TOLERANCE IN WHEAT

Abstract

A Differential Display Polymerase Chain Reaction (DD-PCR) technique was applied for gene expression profiling to detect the up and down regulation of gene expression in shoots and roots of the two cultivars Sahel 1(tolerant) and Gammeiza 7 (sensitive) in response to drought in bread wheat (Triticum aestivum L.). Twenty differentially expressed ESTs fragments were obtained from shoots and roots. The sequences of ESTs were identified by using bioinformatics analysis. Seven of which were from shoots and 13 from roots. The results of fragments showed a significant homology to some predicted proteins such as:TaAP2which has important roles in directing changes in gene expression during stress, glycosyltransferases (GTs) which catalyzes the transfer of sugar moieties to a wide range of acceptor molecules, nelumbo nucifera protein NEN-4whichplays a role in cellular protection, restoration of plant functions under stress and exhibits protein-repair activity after heating to100°C, fructan 1-exohydrolase which is important for regrowth of leaf tissue after defoliation, ageratina adenophora ICE1 proteinthat activates many downstream genes that confer chilling and freezing tolerance to plants. RNA polymerase II gene which regulates transcription, the synthesis of RNA from a DNA template, is one of the most important steps in control of cell growth and differentiation.Serine/threonine-protein kinasemaintains unperturbed photosynthesis inducing an oxidative stress response and plays a role in salt stress signaling, NRC-1which is highly responsive to its environment and provided insights into some of the specific responses at the level of gene expression and prolamine genes stableproteinswhich is accumulatedatmassivelevelsduetothehighexpressionlevel fromextensivelyduplicatedgenesinendoreduplicatedcells. Elucidation of the functions of these genes can understand the signal transduction of response mechanism for drought in the two cultivarswhich can be used to improve the quality and productivity of Egyptian wheat in future investigations. Key words: Triticum aestivum, ESTs, Differential display, drought and signal transduction.