| Drought, high salinity and low temperature are common stress condition that adversely affect plant growth and crop production, which is a global problem. How to promote the resist ability of crops to drought, high salinity and low temperature and then increase crop production is a important question related to the national economy and the people's livelihood. Compared with traditional breeding technique and molecular marker aided selection, it is a more attractive approach to improve the resist ability of crops by plant engineering. But as a result of the complexity of osmotic stress reaction in heredity and physiology, the knowledge about molecular mechanism of osmotic stress is far from necessity, which restrict the application of genetic engineering technique. For example, it is difficult to obtain ideal resist ability when single functional gene was introduced into plants. The last research results showed that some key genes involved in osmotic stress signal transduction, such as DREB and CDPK, regulated the expression of functional genes. Overexpression of these genes in transgenic plants activated endogenesis stress resisted genes, therefore endowed higher resist ablity.According to above-mentioned problems, this study take rice as material to clone key genes during osmotic stress signal transduction, construct plant expression vectors and cultivate transgenic rice. These will provide the foundation for studying osmotic stress resist mechanism and cultivating transgenic rice varieties which resist to osmotic stress.The main results was summarized as follows.1. DREB2A gene was cloned from Arabidopsis thaliana by RT-PCR. The result of sequence analysis showed that the sequence we obtained was the same as that in GenBank.2. A 1700bp fragment was amplified from a salinity resist rice variety, liaoyan 241 by nested RT-PCR using osCDPK.7 gene special primer. It was identified as osCDPK7 gene by endonuclutidase analysis.3. A 1200bp fragment was amplified from a salinity resist rice variety, liaoyan 241 by RT-PCR using osMSRMK2 gene special primer. It was identified as osMSRMK2 gene by nested PCR and endonuclutidase analysis.4. A 2500bp fragment was amplified from a sality resist rice variety, liaoyan 241 genomic DNA by PCR using osMSRMK2 gene special primer. It was identified as osMSRMK2 gene bynested PCR.5. A 1500bp fragment was amplified from a salinity resist rice variety, liaoyan 241 by RT-PCR using osMAPK4 gene special primer. It was identified as osMAPK4 gene by endonuclutidase analysis.6. Eight plant expression vector cassettes were constructed, which were regulated by different promoters, contained different cloning sites and were fit for expression in monocotyledon or dicotyledon respectively. In these vector cassettes pCU and PCE12 were fit for constitutive expression of foreign genes in monocotyledon, pC29A and PCC29A fit for osmotic stress inducible expression of foreign genes in monocotyledon, pBE12 and pBCE12 fit for constitutive expression of foreign genes in dicotyledon, pB29A and pBC29A fit for osmotic stress inducible expression of foreign genes in dicotyledon.7. Four DREB 1A gene plant expression vectors were constructed, which were regulated by different promoters and were fit for expression in monocotyledon or dicotyledon respectively. In these vectors, pCDE12 is fit for constitutive expression of DREB 1A gene inmonocotyledon, pCD29A fit for osmotic stress inducible expression of DREB1A gene in monocotyledon, pBD35s fit for constitutive expression of foreign DREB1A gene in dicotyledon, pBD29A fit for osmotic stress inducible expression of DREB1A gene in dicotyledon.8. Twor DREB2A gene plant expression vectors were constructed, which were regulated by different promoters and were fit for expression in monocotyledon. In these vectors, pCDRE12 is fit for constitutive expression of DREB2A gene in monocotyledon, pCDR29A fit for osmotic stress inducible expression of DREB2A gene in monocotyledon.9. Rice...
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