Two proteins join forces to make flowers

What mechanisms are behind the appearance of flowers ? To answer this question, a 25-year-old enigma has just been solved : The role of the UFO protein in this formation process.

While its nature suggested that it destroys its partners, this protein is in fact an aid to the birth of a flower when it is coupled to the LEAFY protein. This was revealed by researchers from several Grenoble institutes* in a new study published in Nature Plants. Scientists already knew that LEAFY, by binding to specific regions of chromosomes, activated the genes responsible for flower bud formation. They also knew that LEAFY does not act alone, but with the help of the UFO protein. With this new work, the scientists now reveal that UFO’s role is to allow LEAFY to access new regions of the chromosomes, which neither protein can access alone. Thus coupled, they can activate genes that are essential for the formation of buds, petals or stamens. To achieve these results, the scientists combined plant genetics experiments, bioinformatics analyses, but also used protein imaging by cryo-electron microscopy, allowing them to see these two proteins in action. How the LEAFY-UFO pair acts differently in petunia, gerbera, rice or snapdragon remains to be discovered.

CNRS Press info

The F-box protein UFO controls flower development by redirecting the master transcription factor LEAFY to new cis-elements. Rieu P, Turchi L, Thévenon E, Zarkadas E, Nanao M, Chahtane H, Tichtinsky G, Lucas J, Blanc-Mathieu R, Zubieta C, Schoehn G, Parcy F. Nature Plants, 2023,

*Collaboration : This research involved scientists from the Cell & Plant Physiology Laboratory, the Laboratoire translational innovation in medicine and complexity, the Institut de biologie structurale and Integrated Structural Biology Grenoble.

Contact for the protein imaging : G. Schoehn (IBS/Methods and Electron Microscopy Group) & Eleftherios Zarkadas (ISBG)