Synthesis Of A New EPSPS Gene And Study Of Its Function In Tobacco

Glyphosate is an exceptionally reliable, phloem mobile, broadspectrum herbicide with little residual soil activity. The primary target of glyphosate is 5-enolpyruvyl-shikimate-3-phosate synthase (EPSPS), an enzyme in the aromatic amino acids biosynthetic pathway. This pathway is found only in microbes and plants. Because of these desirable properties, glyphosate has been world wide used to control weeds. Unfortunately, toxicity to all plants makes it difficult to apply glyphosate to crops.Herbicides have been widely used to control weeds in China recent years and glyphosate production has been the largest herbicide industry of our country. To extend the application of glyphosate, we aimed at the development of glyphosate-tolerant cultivars through genetic engineering. As a start, we focused on the cloning of a glyphosate-resistant gene which we own intellectual properity and its function test in transgenetic plants.In this study, a newly designed EPSPS gene was chemically synthesized and cloned into binary vector pBINPLUS in which the expression of the EPSPS gene was under the control of double 35S promoter, the Q secquence and NOS terminator. The recombinant plasmid containing the expression cassette was then introduced into Agrobacterium tumefaciens strain LBA4404. Transgenic tobacco plants were obtained by Agrobacterium-mediated leaf disc transformation and their sensitivity to glyphosate was tested. Results showed that most of the transgenic plants identified by PCR Southern survived upon treatment of glyphosate at the concentration of O.5g11, while non-transgenic plants wilted and died. These data proved that the newly synthesised EPSPS gene was able to confer glyphosate resistance to transgenic plants, suggesting a promising application of the gene in crop improvement.