XVI International Botanical Congess

We have used transposon mutagenesis in Arabidopsis (Sundaresan et al. 1995, Genes and Development 9:1797-1810) to screen for mutations in genes regulating cell division and affecting either embryo or gametophyte development. The sporocyteless mutant, in which failure of the switch from mitotic to meiotic cell fate results in the absence of meiocytes, was isolated and molecularly characterized. A mutant defective in female gametophyte development was isolated, and found to carry an insertion into the gene encoding the Arabidopsis homolog of budding yeast Cdc16p and fission yeast cut9p. These yeast proteins are components of the Anaphase Promoting Complex (APC) required for progression through the G2/M transition. The mutants will be useful for studying cell division in higher plants.