摘要:
The invention relates to a method for producing a transformed plant cell. More particularly, the method involves the transformation of a plant cell with a Transformation Cassette which is targeted to plant plastids and which comprises a selection gene, for example isopentenyl transferase (IPT), and a transgene. After selection for transformed plastids, expression of a recombinase is induced in the plant cell, which leads to the excision of the selection gene from the plastid and the expression of the transgene in the plastid. The invention also provides cells and plants comprising the Transformation Cassette.
摘要:
Disclosed is an inducible promoter system in conjunction with a site-specific recombination system which allows (i) specific activation of transgenes at specific times or (ii) excision and removal of transgenes (e.g., antibiotic resistance markers) from transgenic plants. These “suicide” gene cassettes, including the recombination system itself, can be evicted from the plant genome once their function has been exerted. The system is based on the ability to temporally and spatially induce the expression of CRE recombinase which then binds to directly repeated lox sites flanking the transgene in question leading to the precise excision of the gene cassette. Also disclosed is a method to activate an inverted, and therefore silent, transgene by placing two lox sites in opposite orientations flanking the transgene. This results in inversion of the intervening DNA fragment in the presence of CRE recombinase. This activation can be timed by placing the CRE recombinase under the control of an inducible promoter.