XVI International Botanical Congess

Efficient gene targeting in Physcomitrella patens has enabled for the first time in plants the direct application of gene disruption. Yet, to achieve more sophisticated functional studies such as point mutagenesis or promoter replacement, the efficient replacement of genomic sequences by a single copy of an in vitro mutated one must be realized. This question was addressed on the adenine phosphoribosyl transferase locus using both cDNA and genomic DNA based transforming sequences. Our data revealed that gene conversion is very efficient in Physcomitrella with DNA structure and sequence homology requirement similar to those observed in yeast. Thus Physcomitrella patens provides the only plant model system in which the sophisticated reverse genetic approaches developed in yeast can be applied to study plant biology.