Non-autonomy of AGAMOUS function in flower development: use of a Cre/loxP method for mosaic analysis in Arabidopsis

Angiosperms use a multi-layered meristem (typically L1, L2 and L3) to produ ce primordia that then develop into plant organs, A number of experiments s how that communication between the cell layers is important for normal deve lopment. We examined whether the function of the flower developmental contr ol gene AGAMOUS involves communication across these layers. We developed a mosaic strategy using the Cre/loxP site-specific recombinase system, and id entified the sector structure for mosaics that produced mutant flowers. The major conclusions were that (1) AGAMOUS must be active in the L2 for stami noid and carpelloid tissues, (2) that AGAMOUS must be active in the L2 and the L3 for floral meristem determinacy, and (3) that epidermal cell identit y can be communicated by the L2 to the L1 layer.