Abstract
Cell differentiation involves temporally and spatially distinct stages, in which cell fate is established by an appropriate genetic program and then maintained by epigenetic regulation through the subsequent mitotic events. We identified a novel mutant, named bouquet-1 (boq-1), exhibiting frequent stem fasciation caused by the postembryonic development of extra shoot apical meristems in a SHOOT MERISTEMLESS (STM)-dependent manner. The boq-1 mutation enhanced adventitious meristematic activity observed in the stm mutant, and partially suppressed the floral defects in the stm and wuschel mutants. Molecular cloning revealed that the BOQ gene encodes a WD40 repeat protein. Overproduction of the boq-1 allele in the wild-type background mimicked the boq-1 phenotypes in a dose-dependent manner, suggesting that the mutant BOQ-1 protein acts in a dominant negative manner. Taking these results together, we propose that the BOQ gene is involved in the epigenetic regulation of cell differentiation directly or indirectly in a novel fashion.
