Many laboratories have set up several foreign gene transformation systems for rice. But these transformation systems were all used T DNA system of Ti plasmid, then the foreign gene integrated into plant genomes DNA by means of the insertion of both ends of T DNA. The integrated target of T DNA in plant genome DNA is random, while the thoroughly random integration would interfere with self stable system of plant genome, which could lead to pernicious mutation. In this study, according to the mechanism of homologous recombination, we had constructed a new donor plasmid for indica rice.It would cause the foreign gene intergated into chromsomal rDNA locus. According to the known sequence of ribosomal DNA, we cloned the 2.5kb fragment of it by PCR, and used the fragment as the integrated homologous sequence. After subcloning foreign DNA including nptII gene and metallothionein gene at the end of homologous fragment, the donor plasmid pURKMT which will integrate into the genomes DNA of indica rice was constructed. Then, donor plasmid pURKMT was introduced into calli of indica rice (Jiahe NO.7) by electroporation. Screened by kanamycin, the transformant calli which was integrated the foreign DNA were selected. Dot blotting data showed that the foreign DNA including nptII gene and MT gene has integrated into rice genome DNA.
Journal of Xiamen University(Natural Science)