During sexual reproduction, multicellular organisms must produce haploid cells, whose fusion at fertilization will restore the original diploid status. A specialized cell division, meiosis, leads to the formation of these haploid cells and is therefore a crucial step in the process of reproduction since any meiotic abnormality can lead to infertility or to major genetic defects in the offspring. In addition, it is during meiosis that genetic recombination occurs, providing a large part of the population diversity. A better understanding of meiotic mechanisms, in addition to its intrinsic fundamental interest, may find applications in plant breeding, whether to control reproduction (apomixis) or the distribution and frequency of recombination events.
Another application of the control of recombination, somatic this time, is gene targeting. Gene targeting is an essential tool for studying gene function, as it allows specific modification of virtually any genomic sequence. The control of gene targeting is also a prerequisite for safe and acceptable GMOs. The moss Physcomitrella patens is the only known higher eukaryote where gene targeting efficiency is comparable to that of the yeast Saccharomyces cerevisiae. Gene targeting recruits enzymes of the somatic homologous recombination pathways involved in DNA double-strand break repair and more generally in genome stability. Better knowledge of the mechanisms involved in somatic recombination repair in Physcomitrella patens should enable a better understanding of gene targeting and ultimately allow a transfer of this tool to other species.
Our projects aim to bring together complementary skills (genetics, cytology, molecular biology and protein biochemistry), complementary models (Arabidopsis thaliana, Physcomitrella patens, Brassica napus) to better understand the key stages of meiosis and the somatic and meiotic recombination in plants.