Comparative Study On Lignin Biosynthetic Metabolites Analysis In Transgenic Tobacco

4-coumart:coenzyme A ligase is a key group of enzymes controlling a continuous metabolic flux from the plant phenypropanoid metablic pathway into the biosynthesis of lignin ,so it is entry-point enzymes in the lignin biosynthetic pathway .4Cl converts 4-coumaric acid(PA), caffic acid(CA), ferulic acid(FA) and sinapic acid(SA),into the corresponding CoA esters ,serving as substrates into various branch pathway. The level of the enzymatic activity and that of the transcript for 4CL affect the content of lignin even composition in some plants.There is interesting to use 4CL gene for the genetic imporovement of lignin for plant material.At the same time,knowledge of the activity and the substrate specificity of enzyme and the role in the lignin biosynthetic pathway will be important efforts to genetically engineer lignin biosynthesis.Separation and determination of caffic acid, 4-coumaric acid and ferulic acid,secondary metablits in the lignin biosynthetic pathway and three substrates of 4CL,is significant for understanding the role of the of enzyme 4CL in the lignin biosynthetic pathway.The content of study as following:The antisense-4CL1 gene was transformed into tobacco by agrobacterium-mediated transformation system Transgenic plants were identified with Southern blotting analysis.Transplanting and culturing transgenic tobaccos,they have no morphological difference among these transgenic plants and between transgenic plants and control plant.High performance liquid chromatography has been developed for separation and determination of caffic acid, 4-coumaric acid and ferulic acid in transgenic tobacco. The optimized separation conditions were suggested. These results show that the assay is successful for quantitative analysis of them.