Determinants of transcription factor specificity in flowering time and flower development in Arabidopsis thaliana

The induction of flowering is critical for the reproductive success of plants and is therefore controlled by an intricate regulatory network comprised of numerous transcription factors expressed at the shoot apical meristem (SAM), the tissue from which plants produce new organs.

The bZIP transcription factor FD and the plant-specific transcription factor LEAFY (LFY) play key roles in regulating the timing of flowering and the formation of floral organs in Arabidopsis thaliana, respectively.

Interestingly, our preliminary results indicate that the FD and LFY proteins are part of a novel transcription factor complex that at the SAM binds to a previously unknown DNA motif, which differs remarkably from the canonical FD and LFY binding sites. We refer to this novel DNA motif as MEDALS (Meristem spEcific fD And Lfy Site).

Here, we propose a series of experiments that will characterize the determinants of FD-LFY binding to MEDALS, identify cofactors required for meristem-specific DNA binding of the FD-LFY complex, and investigate the biological relevance of binding of FD-LFY to MEDALS.

In the long term, the proposed project will provide valuable insight not only into the function of FD and LFY proteins as key regulators of flowering and floral development but will also shed light on how the formation of transcription factor complexes can modulate DNA binding properties at the genome-wide scale to obtain temporal-spatial specificity.