The PI proposes to evaluate the possibility of gene targeting in somatic plant cells. The experiment involves first the introduction of a mutant selectable marker gene and the establishment of a set of stable transformants. These mutant lines will then be secondarily transformed with a complimentary mutant in the same selectable marker gene. At this time selection will be imposed so as to identify transformed cells in which there has been site specific recombination between these complimentary mutants thereby reconstructing a functional selectable marker gene. The molecular details of this event will be examined. This technology could allow for gene replacement or inactivation in plant cells and targeting of sequentially introduced traits to a single locus to expedite plant variety improvement.
