| Lettuce(Lactuca sativa L.), feverfew, lettuce genus, It contains fewer calories than lots of other vegetables and is a kinds of delicious foods. It takes only a short time to produce Lettuce, and most parts of it can be eaten. When it is used into science, the rate of regeneration of its callus and shoots formation is frequent, and the operation is easy. It is an excellent acceptor for Plant Genetic Transformation to express extrinsic protein.The America speed-grow lettuce was used as materials in this research. At first, tests were done on the most suitable culture medium for cotyledons regeneration, the most suitable dark culture time and the suitable Hygromycin concentration for successful transformer selection when callus differentiation and take root. The most suitable callus inducement culture medium for the America speed-grow lettuce is MS+6BA1.0mg/l+NAA0.2mg/l. The most suitable callus differentiation culture medium is 1/2MS. The most suitable dark culture time is 5 days. The appropriate Hygromycin concentration for callus differentiation is 35mg/L and for take root is 30mg/L.Carotenoids Biosynthesis Enzyme Gene (PSY) was transform into the America speed-grow lettuce by Agrobactorium tumefacien. The several factors influencing the transformation such as Agrobactorium concentration, dip time, co-culture time, whether or not to additive AS have been studied in the test.The suitable OD600 of engineering bacterial suspension range were from 0.4 to 0.6 for infection. The suitable time was 10-15 mins for callus to be infected by Agrobactorium. The most effective result could be obtained when the co-culture time was 2 days. The addition of 100μmol/LAS and recultivate could increase the induction frequency of resistance callus and shoots. In the test we have obtained the resistance plants for Hygromycin are 5.It was originally proved by the PCR examination and PCR-Southern analysis that the target gene PSY has been transferred into the lettuce genome. 2 positive plant were obtained.
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