Establishment Of Gene Transformation Via Plant Apical Meristem

Technology of gene transformation, which has been developing since 1980s and named "the second green revolution", has modified the characters of plants at the gene level, broken the barriers of the different species and expand the scope of breeding. Nowadays, through the research for more than 20 years, two systems—Agrobacterium and Particle gun—have been established and prevail for plant transformation.However, some existing problems need solving. The key point for gene transformation is to establish an efficient object system. The current transformation methods mainly depend on the culture approach of dedifferentiation and re-differentiation of plant cells to transfer foreign genes and obtain transgenic plants. But this culture approach has some limitations—the ability for dedifferentiation and re-differentiation depends on the genotype and source of the explants, and this approach lead to the phenomenon of somaclonal variation, fertility decrease or loss. So, it is very significant to establish a transformation method without callus culture and limitation of genotype.Using plant meristem for gene transformation will avoid callus culture, so somaclonal variation can be reduced and the foreign gene can be put down stably.This experiment firstly used tobacco as the object to prove that plant meristem is suitable for in vivo direct gene transformation. Tobacco axillary meristem was exposed and wounded with fiber glass brush as the object for agrobacterium gene transformation. Then the axillary buds were cut down and induced to take roots in the medium. After the antibiotics selection, 23 were proven to gain kanamycin resistance. Besides, 13 were shown Gus positive and 8 of them were proven as transgenic plants with PCR and Dot Blotting tests. Further, the wheat apical meristem was used to test the possibility of plant direct transformation. The stem apical meristem was exposed and wounded for agrobacterium gene transformation, and 100mg/L kanamycin was used for antibiotics selection. Finally 24 plants showed kanamycin resistance and one was proven PCR positive. Transformation of apical meristem is an effective attempt to search a new rapid convenient method for plant transformation.