How does the plant know when its springtime? Imaizumi et al. now add some of the molecular details to the fascinating subcellular signaling process involved as plants respond to increases in day length. As the days lengthen, so does the window of opportunity through which one protein, expressed in a daily cyclical pattern, can degrade its target. With longer days, the target suffers increasing degradation, removing its repression of the protein CONSTANS, thus allowing flowering to proceed.
T. Imaizumi, T. F. Schultz, F. G. Harmon, L. A. Ho, S. A. Kay, FKF1 F-box protein mediates cyclic degradation of a repressor of CONSTANS in Arabidopsis. Science 309, 293-297 (2005). [Abstract] [Full Text]