A LEAFY link from outer space

Abstract

The beautiful shape and colour patterns of flowers attract almost everybody, including developmental biologists. Studies of floral patterning have shown that the identity of floral organs is determined by a combinatorial code of homeotic genes, termed A, B and C, expressed in three separate regions of the flower. This knowledge allows scientists (and biotech companies) to manipulate flowers to form organs at any position, yet the secret of how the three activities are put into the right place remains hidden. But on page 561 of this issue, Parcy et al. bring new insights to this matter. They show that the LEAFY (LFY) protein is directly involved in activating the transcription of homeotic genes, together with at least one co-regulator, UNUSUAL FLORAL ORGANS (UFO). The genes that encode these proteins were originally isolated as floricaula and fimbriata in a flower that almost all of us have manipulated as children, the snapdragon.