| The method by particle bombardment is considered to be an effective way for wheat genetic transformation, and is widely used in many aspects. But this method has some drawbacks such as high cost and low transformation efficiency. In 1992,Vasil transformed wheat using this method for the first time.And then Cheng obtained normal transgenic wheat mediated by A.tumefaciens in 1997,followed by Xia Guangmin and Ye Xingguo.It is necessary to perfect the method of A.tumefaciens infection because of different genotypes and transformation system of wheat. However,the method has many advantanges compared with others'. Firstly,high transformation efficiency. Secondly,high frequency of single copy. Third,fit for great DNA segments transformation. Fourth,stability of expression of transgene. At last,low cost and easily to manipulation. Therefore, it is significant to pay more attention to wheat complex genomes and focus on study of this transfection system.In this study,immature embryo calli of Wheat'Luoyang8716'and'Mianyang19'was infected by A.tumefaciens strains with vector pCAMBIA3301. There are three strains( GV3101, EHA105, and LBA4404 ), four concentration gradient of the strains(OD600:0.2,0.5,0.7,1.0) and three time parameters (10, 30, 60min) used in this experiment, totally having 36 processing and four repeat treatment for each processing. The result indicated that the condition of'OD6001.0×10min'and'OD6000.5×30min'was optimal for A.tumefaciens infection.The efficiency of instantaneous expression was even up to 50-70%.After precultured for 3-5d in the dark, co-cultivated embryo calli with A.tumefaciens at 24±1℃for 3-4d,debacterium at 350mg/L carbenicillin and selected at 5mg/L PPT, transgene fragments in transgenic plant were determined by PCR amplification. It is concluded that transformation average efficiency can add up to 0.45%.
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