Optimization of Agrobacterium tumefaciens-mediated transformation systems in tea plant (Camellia sinensis (L.) O. Kuntze)

The cotyledon callus of Camellia sinensis were used as the receptors for transformation by Agrobacterium tumefaciens EHA105 containing PS1aG-3. Some factors which affected the result of Agrobacterium-mediated transformation of C. sinensis were studied on the basis of GUS transient expression system. The optimum system of Agrobacterium-mediated transformation was that the cotyledon callus were pre-cultured for 3 d, and then infected for 15 min by EHA105 followed by 3 d co-culture in the dark on the YEB medium containing 150 μmol L^-1 AS. The transient expression rate of GUS gene was 62.6%. An appropriate time of delayed selective culture could improve the conversion rate of the tea callus. After delaying the selective culture for 3 d, infected callus were transferred into the differentiation medium and the root induction medium, both of which were supplemented with 100 mg L^-1 Spectinomycin, in the end resistant seedlings of C. sinensis were obtained. The conversion rate was about 3.6%.