The induction of flowering is of major importance from an ecological and agronomic point of view. Timely and synchronous flowering is essential to optimize pollination and allow seed production and maturation under favorable environmental conditions. Environmental factors, including light in particular, regulate flowering time, the mechanisms of which have been the subject of many studies. However, these experiments are usually performed in growth chambers in the absence of UV-B, a type of radiation that is a natural component of sunlight and, for example, is responsible for sunburns in humans. A team from the University of Geneva (UNIGE) has discovered that UV-B can be a powerful inducer of flowering, but that a protein called RUP2 blocks its action to prevent early flowering. This work is published in the journal Genes & Development.