Characterization of a new mutant allele of theArabidopsis Flowering Locus D (FLD) gene that controls the flowering time by repressingFLC

Flowering in higher plants is controlled by both the internal and environmental cues. InArabidopsis, several major genetic loci have been defined as the key switches to control flowering. TheFlowering Locus C (FLC) gene has been shown in the autonomous pathway to inhibit the vegetative-to-reproductive transition.FLC appears to be repressed byFlowering Locus D (FLD), which encodes a component of the histone deacetylase complex. Here we report the identification and characterization of a new mutant allelefld-5. Genetic analysis indicates thatfld-5 (in the Wassilewskija background) is allelic to the previously characterizedfld-3 andfld-4 (in the Colombia-0 background). Genetic and molecular analyses reveal thatfld-5 carries a frame-shift mutation, resulting in a premature termination of theFLD open reading frame. TheFLC expression is remarkably increased infld-5, which presumably attributes to the extremely delayed flowering phenotype of the mutant.