고려대학교 생명과학대학 생명과학부/ 대학원 분자생명과학과

The earth’s revolution and rotation makes day and night cycle in every day, and long and short days in every year. The plants have evolved to sensitively respond to seasonal changes in photoperiod for flowering; the long-day plants induces flowering in extended day length conditions, and the short-day plants induces flowering by responding to extended night length. However, it does not clearly understand the floral induction mechanisms. Here, we show the molecular genetic mechanism of how plants recognizes the light information and regulates flowering time using the dicot model plant Arabidopsis thaliana. In the afternoon of long days, a blue-light receptor FKF1 F-box protein is expressed and activated by light, and represses the activity of COP1, a strong repressor of flowering, resulting in early flowering in long days. In the afternoon of short days, however, FKF1 is expressed in the dark; the unilluminated FKF1 does not interacts with COP1 or inhibit the floral repressor activity of COP1, leading to late flowering in short days. Our findings provide more insights into the mechanisms of flowering-time control in response to seasonal changes in day length.