XVI International Botanical Congess

The genetic and molecular basis controlling megagameto-genesis is largely unknown. We use enhancer detection to identify genes involved in the development of the female gametophyte. We identified lines with expression specific to all four gametophytic cell types suggesting a role of these genes in cell specification or specific functions of these cells. Among 5,000 transposants, we identified about 50 mutants affecting the gametophytic phase of the plant life cycle, 15 of which were characterized in detail. They affect different stages of gametophyte development such as the nuclear division cycles, cell degeneration, fertilization and karyogamy. Sequences flanking more than 120 insertions were sequenced. Many are similar to regulatory factors and signal molecules but also to proteins involved in basic cellular processes