Analysis of homeotic flower mutants has revealed that the identity of floral organs is specified by a limited set of key regulatory genes, acting alone and in combination. A model, now known widely as the ABC model, has been shown to apply to a range of plant species (Coen and Meyerowitz, 1991; Weigel and Meyerowitz, 1994). A key regulatory gene specifying carpel identity in Arabidopsis flowers...

The Arabidopsis homeotic protein AGAMOUS (AG), a MADS domain transcription factor, specifies reproductive organ identity during flower development. Using a binding assay and expression analysis, we identified a direct target of AG, GIANT KILLER (GIK), which fine-tunes the expression of multiple genes downstream of AG. The GIK protein contains an AT-hook DNA binding motif that is widely found in...

The Arabidopsis thaliana floral homeotic gene AGAMOUS (AG) plays a central role in reproductive organ (stamen and carpel) development. AG RNA is expressed in the center of floral primordia from a time prior to the initiation of stamen and carpel primordia until late in flower development. While early AG expression acts in specification of stamens and carpels, the role, if any, of continued AG e...

We investigated the ability of RNA interference (RNAi) directed against two co-orthologs of AGAMOUS (AG) from Malus domestica (domestic apple, MdAG) to reduce the risks of invasiveness and provide genetic containment of transgenes, while also promoting the attractiveness of flowers for ornamental usage. Suppression of two MdAG-like genes, MdMADS15 and MdMADS22, led to the production of trees wi...

The floral organ identity factor AGAMOUS (AG) is a key regulator of Arabidopsis thaliana flower development, where it is involved in the formation of the reproductive floral organs as well as in the control of meristem determinacy. To obtain insights into how AG specifies organ fate, we determined the genes and processes acting downstream of this C function regulator during early flower develop...

Postzygotic lethality of interspecies hybrids can result from differences in gene expression, copy number, or coding sequence and can be overcome by altering parental genome dosage. In crosses between Arabidopsis thaliana and A. arenosa, embryo arrest is associated with endosperm hyperproliferation and delayed development similar to paternal-excess interploidy crosses and polycomb-repressive co...

The genes and pathways AG regulates in late-stage flower development are largely unknown. Several putative downstream genes of AG involved in anther dehiscence were identified, including DAD1, MYB26, OPR3, COI1, and RBR1, through a bioinformatics approach. A 35S::AG-GR inducible line was constructed for timed-induction expression analysis of anther dehiscence versus indehiscence, which revealed...