Construction Of Expression Vector Containing A Novel Stress-tolerant Gene-TaLEA₂ From Wheat And Analysis Of The Stress Tolerance On Transgenic Plants

During their growths, crops often suffer from adverse environmental stresses such as salinity, drought and low temperature. Among them, the drought causes most serious damage and badly influence on the yields of crops. Wheat is an important crop in the world, the output of which is on the top of all other crops. On the other hand, the farmland is limited and the population increases continuously at recently, Therefore, the object of plant breeding is always to breed crop varieties with relatively drought tolerance. Developing anti-drought agriculture has its important and realistic significance.It is drought that make the water content of plant cell limited and that cause the osmotic pressure higher. During the course of the long-trebly evolution, high plants underwent a serious of changes in their physiology or growth to respond to the water-stress of environment. The expression of water-stress inducible gene is to produce some important functional or regulatory proteins to protect plant cell from injuries, and to make plants engender their defense mechanisms against the environment. Among them, the osmoregulation is an important mechanism of physiology by which the plants fit the adverse circumstances. Late-embryogenesis -abundant protein (LEA protein) is a kind of protective agent of dehydration, which can protect biological macromolecules from the water-stress of environment, especially in maintaining the cell membrane stability, and mitigating the injuries of the drought. The investigations of the group 3 LEA protein and gene showed that these gene expressions or protein accumulation had positive correlation with the botanical osmotic pressure, and it has confirmed that the group 3 LEA gene may have the function protecting from drought. TaLEA2 is one of the group 3 LEA gene cloned from wheat by being dried for 48 hours. The research of ex-period indicated that over-expression of TaLEA2 gene in yeast improved its growth status and survival from the osmotic pressure compared with the wild type.The main object of investigate is to clone and identify the TaLEA2 gene of group 3 LEA from wheat, combining the transgenic technique and the method of physiology or biochemistry, study the relation between TaLEA2 gene and crops stress tolerance, and got the following result.1. One of the group 3 LEA, TaLEA2 gene, of wheat were cloned into pBI121 with CaMV35S promoter, and excised the GUS gene. An high efficient plant expression-vector pBI121-TaLEA2 was successfully constructed. The determining rank indicated that the sequence of TaLEA2 gene was 664bp long, this gene segment has a 636bp...