CLAVATA1, A REGULATOR OF MERISTEM AND FLOWER DEVELOPMENT IN ARABIDOPSIS

We have investigated the effects on plant development of mutations in the Arabidopsis thaliana CLAVATA1 gene. In clavata1 plants, vegetative , inflorescence and floral meristems are all enlarged relative to wild type. The apical meristem can fasciate in the more severe mutant alle les, and this fasciation can occur prior to the transition to flowerin g. Flowers of clavata1 plants can have increased numbers of organs in all four whorls, and can also have additional whorls not present in wi ld-type flowers. Double mutant combinations of clavata1 with agamous, apetala2, apetala3 and pistillata indicate that CLAVATA1 controls the underlying floral meristem structure upon which these homeotic genes a ct. Double mutant combinations of clavata1 with apetala1 and leafy ind icate CLAVATA1 plays a role in establishing and maintaining floral mer istem identity, in addition to its role in controlling meristem size. In support of this, RNA expression patterns of AGAMOUS and APETALA1 ar e altered in clavata1 flowers.