Expression Of CP4EPSPS Under The Control Of Leafy Promoter Enhances Glyphosate Tolerance In Tobacco Budlet

Glyphosate is a kind of broad-spectrum, inner-absorption conducting herbicides. Because it can also kill the crops, time and areas of usage are limited. With the planting area of transgenic plants enlarged in the global field, the use of glyphosate becomes more and more extensive. But in the reported glyphosate-resistant transgenic plants the constitutive promoters were used to drive the extraneous gene expression. The constitutive promoters make all parts of the transginc plants in the development and metabolic stage efficiently express glyphosate-resistant gene, which would no doubt cause plants a huge burden in metabolism and a great waste in the material and energy.Based on the mutant research of flower development process, Leafy, the meristematic tissue specific gene separated from Arabidopsis thaliana, plays an extremely important role in plant development. Research and analysis of the promoter area has indicated the functions of apical meristem specificity expression.Continuous and efficient expression in transgenic plants of glyphosate-resistance gene increases the plants metabolism pressure, even changes the plant forms. To reduce the burden of plant metabolism and waste of energy, the purpose of this study is that we use Leafy tissue specificity promoter to drive the expression of5-enolpyruvylshikimate-3-phosphate synthase gene (CP4EPSPS) in the budlet of the transgenic plants to improve the capacity of glyphosate-resistance. The expression of CP4EPSPS under the control of Leafy promoter could reduce the metabolism and energy waste, and the specific expression in budler of transgenic plants, when spraying in glyphosate, can significantly reduce the extent of the damage of the transgenic plants. They expanded the sensitive degree to herbicides between transgenic plants and weeds, and made the injured extent reduce to the lowest level. Hence the crops production would enhance greatly.The study cloned a Leafy promoter from genome of Arabidopsis thaliana, and the on-line analysis of PLACE and PlantCARE indicated that the promoter had the specified structure TATA-box and CAAT-box, at the same time there are still kinds of the cis-acting elements such as light response elements, ABA response elements and MYB binding sites. Instead of CaMV35S promoter, Leafy promoter fused with CP4EPSPS gene which was changed and added transit peptide of rubisco small ribosome subunit. Meanwhile used Leafy promoter to regulate the gus gene, a reporter gene. Constructed two plant expression vectors and named p3301-Leafy-gus, p3300-Leafy-CP4EPSPS. By the detection of PCR and RT-PCR to transgenic tabaccos, the extraneous genes were successfully transformed into the genome of tabaccos. Stable expression and GUS staining showed that the activities of Leafy promoter were only detected in stem apex and extremely young apical leaves of transgenic tobaccos. The gus activities can not be detected in mature leaves, stems and roots. The results of glyphosate-resistance showed that the budlet part in transgenic tobaccos showed tolerance to the herbicide glyphosate. All research indicated that CP4EPSPS gene expression driven by Leafy promoter enhanced the glyphosate tolerance in the budlet part of transgenic plants.