Abstract
In the leaves of many higher plants, the tissues on the adaxial (upper) and abaxial (lower) sides are morphologically different, owing to genes specifically expressed on the respective sides. Adaxial-abaxial polarity pre-formed in leaf primordial will guide the specific expression. However the molecular mechanism of the process is not understood yet.
FILAMENTOUS FLOWER (FIL) is an abaxial specific gene and the abaxial side specific expression initiate in early stages of the leaf development. We isolated a mutant, #2.0-07-4, where the FIL-expressing region is expanded. In mature leaves of #2.0-07-4, the adaxial tissues resemble spongy tissues observed on the abaxial side in wild type leaves. These results suggest that the responsible gene has a role in restricting the expression of an abaxial specific gene in the proper region and keeping the adaxial tissues from abaxialization in wild type plants.
