Abstract
Flowering in Arabidopsis is regulated by several interacting pathways. Recent studies have shown that genes such as FT, SOC1/AGL20, and LFY integrate signals from these pathways to direct the floral transition. We have been interested in factors acting downstream of FT. The late-flowering gene FD is a good candidate for such genes. The FD activity seems to be required for the early-flowering phenotype of 35S::FT, because otherwise very weak fd-1 mutation strongly suppresses 35S::FT phenotype. FD encodes a bZIP transcription factor. Because fd;lfy has a phenotype indistinguishable from ft;lfy, it is likely that FT acts through FD in AP1 regulation. Dominant late-flowering fwa mutation is an epigenetic mutation that causes ectopic expression of FWA due to promoter hypomethylation. Genetic analysis suggests that FWA blocks the pathway at FT and/or downstream of FT. We envisage that FWA may provide unique tools to dissect pathway from FT to flowering.
