Tht Analysis Of Dehydrin Gene WZY2 Expression In Different Genotypes Wheat Under Drought Stress

Plants can be induced to generate many substances to protect their own normal growth and development under drought and other environmental stresses. Dehydrin is one of such induced proteins which belongs to Late Embryogenesis Abundant protein (LEA protein) family, or LEA-Ⅱfamily. It has K fragments in its sequence, which is a highly conservative fragment formed by 15 amino acids (EKKGIMDKIKEKLPG). The molecular weight of dehydrin is 9～200kD. Dehydrins generally locate in different parts of cell, such as cytoplasm, nuclei, mitochondria and they are drought-inducable proteins that widely exist in higher plants. Structure analysis of dehydrins in different plants shows that dehydrins have the characteristic of hydrophilic and thermal stability, which plays an important role in plants under stressful conditions. At transcriptional level, the expressional quantity of dehydrins directly influence the expression of proteins, thus leads to the responce to drought.To study the relation between the expression of dehydrin gene wzy2 and drought level, and explore the expression variation of wzy2 in different development stages and breeds, four breeds of wheat were taken as material and Real-time quantitative PCR was conducted to study the change of expression quantity of wzy2 in four important development stages (Seedling, Jointing, Tillering, Flowering) under natural drought conditions.The main results of this study are as follows,1.The expression of wzy2 in different genotype varies in different stages under drought. The transcription level correlates positively with drought level in drought-resistance ShanHe 6# and High drought tolerance, which is higher than in drought sensitive wheat. In drought sensitive ZhengYin1#and Low drought tolerance,the expression of wzy2 displays a certain degree of volatility and it strongly expresses in the early stage of drought. The expression of wzy2 decreases rapidly in ShanHe 6#and High drought tolerance when they are rehydrated, and then comes back to initial value before drought. While in ZhengYin1#and Low drought tolerance it slightly increases after rehydration and came back to initial level. That means ShanHe6#and High drought tolerance have stronger drought-resistance ability than ZhengYin1#and Low drought tolerance. 2.The expression of wzy2 in ShanHe 6# and ZhengYin 1# has significant difference in jointing period. From seedling to flowering, the expression of wzy2 varies notably in the samples, except in ZhengYin1#.In flowering period, the expression difference of wzy2 is not so clear. That means the expression of wzy2 may be affected by other conditions such as low temperature and development stage. There are many factors that affect the expression of wzy2 and the internal mechanism is very complex.3.The relative quantitative method to study dehydrin gene wzy2 was established.With this method, comparative data of dehydrin gene expression was obtained. The wzy2 gene is induced by drought in the entire growth period, and does not specifically relate to growth period. As a drought resistance gene, the data can be used as a measurement of the stress tolerance ability and applied in the genetic modifications of improving drought resistance of plant.