The Study On Activities Of Cucumber Phenylpropanoid Metabolism's Key Enzymes And Gene Expression

Phenylapranoid etabolism is a important process for plant to synthesize secondary metabolites. After that, lignin synthesizing and flavonoid synthesizing are the two main synthesizing processes, which will produce phenylalanine metabolites. These phenylalanine metabolites include coumarin,flavonol, lignin,and other Benzenes. They are used as plant antitoxin,UV Protective factors,flower an fruit pigment,cell wall constituent, Signaling molecules and so on ,which play important roles in the plant growth and development. Especially, lignin and others from phenylalanine metabolism play very important roles in plant disease resistance. The key enzyme of phenylalanine metabolism incude PAL,C4H,4CL,CHS,ect. So the research of the enzyme about phenylalanine metabolism is very important for plant disease resistance.Cucumber is one of the top ten vegetable crops. As the all Seasonal vegetable,its production will impact our life deeply. But in the growth of cucumber,it is often attacked by pathogen,such as downy mildew,gray mold,powdery mildew,blight and so on, which cucumber is easy suffered. Downy mildew is the most important factor that impacts the production of cucumber.High-temperature Sealing Treatment is an effective method for prevent and cure downy mildew. As the inducer, salicylic acid can increase plant's resistance. So we compare two kinds of cucumber which have different resistance here(easy infected changchunmici and hard infected jinchun 4). After two kinds of high temperature cucumber by salicylic acid and high temperature on the PAL activity and by semi-quantitative RT-PCR method of salicylic acid, high temperatures and downy mildew of phenylpropanoid pathway gene expression of key enzymes, and further study of benzene Propane metabolism in ways and the relationship between cucumber downy mildew resistance. Preliminary conclusions are as follows:(1) Analysing the activity changes of cucumber under salicylic acid and high temperature, the hard infected cucumber sample's PAL activity is higher than the easy infected cucumber sample's Under the same treatment conditions on the whole.(2) According to the known full-length and partial fragments of genes, we design and synthesis PAL, C4H, CHS, Actin, 18sRNA'Bi-directional primers and increase PCR in it. Then we make sequence of all the result and compare the results with the data from NCBI web in Blast. It's proved that the DNA segment we got in our design is the target segment.(3) Compare the expression of Actin with stability 18sRNA,we choose Actin to be the inter reference gene phenylalanine metabolism key gene semi-quantitative RT-PCR. The result shows that after high temperature treatment , the PAL gene expression in these two kinds of cucumber both arise when the temperature arise and time passes. But changchunmici's gene expression at 48.5℃is bigger than its at 47℃.Jinchun 4's gene expression do not change as the congdition changes; in Changchunmici, the gene expression of C4H arise at 47℃for 1-2 h and get down at 48.5℃. The gene expression arise in C4H gene in Jinchun 4'; CHS changes little while the temperature arise and time passes. gene expression when cut; Jinchun 4 gene expression in raised; PAL As the temperature rising and deal with the extension of time CHS express has changed little. After the rhizosphere, PAL , C4H, CHS three gene expression are raised, Raised amplitude of the three gene are greater in Jinchun 4.After inoculated Pseudoperonospora cubensis with cucumber, PAL expression reaches a peak in 2d12h.