Almost in a Day’s Work

Abstract

Many plants coordinate their annual time of flowering with particular seasons of the year, and one indicator that they use to determine the change of seasons is day length. Sawa et al . (see the Perspective by Rubio and Deng) provide some insights into the molecular interactions that translate day length into flowering initiation. The day needs to be long enough for the blue-light stimulated expression of the proteins FKF1 (flavin-binding, kelch repeat, F-box1) and GIGANTIA (GI) to coordinate. The daily rise in expression of GI lags far enough behind the daily rise in expression of FKF1 that, in the shorter days of the year, daylight has waned by the time there is enough GI to form complexes with FKF1. With the longer days of spring and summer, there is enough time to form complexes and signal to the CONSTANS gene to trigger the flowering pathway. M. Sawa, D. A. Nusinow, S. A. Kay, T. Imaizumi, FKF1 and GIGANTEA complex formation is required for day-length measurement in Arabidopsis . Science 318 , 261-265 (2007). [Abstract] [Full Text] V. Rubio, X. W. Deng, Standing on the shoulders of GIGANTEA. Science 318 , 206-207 (2007). [Summary] [Full Text]