Patent ID: 7112721

Claim:
A method for preparing a transformed plant, comprising: (a) introducing into plant cells a construct comprising, in the 5′ to 3′ direction: a right Agrobacterium T-DNA border sequence; a T-DNA oncogenic region of an Agrobacterium Ti-plasmid, said T-DNA oncogenic region comprising the full complement of oncogenes found in wild-type Agrobacterium T-DNA; a left Agrobacterium T-DNA border sequence; and first and second recombinase recognition sites intermediate to said right and left T-DNA border sequences; said construct further comprising a recombinase coding sequence encoding a recombinase that recognizes said first and second recombinase recognition sites, said recombinase coding sequence being under the control of an inducible promoter; to obtain transformed cells comprising said construct; the presence of said T-DNA oncogenic region in said transformed cells resulting in tumor formation; (b) culturing said transformed cells under conditions that are insufficient for the growth of untransformed cells and that are sufficient for said transformed cells to form tumor tissue, whereby transformed cells are selected; and (c) negating the effect of said T-DNA oncogenic region in said transformed cells by excising at least a portion of said T-DNA oncogenic region with said recombinase; and regenerating morphologically normal transformed plants from said transformed cells.