Gerichte genmodifcatie in planten.

Current transgene technology in plants involves integration of foreign DNA at essentially random positions in the genome and hence results in either the addition of new genes or in random gene disruption. In situ modification or directed disruption of a particular gene (gene targeting) is not yet feasible, despite considerable interest from industry and academia and the far-reaching application potential of such technology. Indeed, the possibility to modify genes in a directed way would offer unprecedented opportunities for rational modification of crop plant genomes, for crop improvement through the creation of new variability and for generation of modified plants that are more readily accepted than the current GMOs. Moreover, gene targeting is also the method of choice for analysis of gene function through reverse genetics, as witnessed by its application in species for which a gene targeting system is well established (e.g. the mouse, several lower eukaryotes and prokaryotes).



We aim to develop technology for targeted mutation of genes in plants following two novel strategies. One is based on homologous recombination through presentation of a targeting construct during meiosis. In meiosis the chromatin architecture, homology searching functions and recombination enzymes are available and adapted to homologous recombination, whereas illegitimate recombination should be restricted. These features are expected to favour homologous over illegitimate recombination. A second strategy is based on the interaction between the genomic sequence to be modified and RNA derived from a silencing locus. Cross-talk between genomic DNA and RNA during post-transcriptional silencing has been documented.