Abstract
Night-break (NB) light pulses suppress flowering in short-day plants. It has been shown that suppression of Hd3a is the cause of the NB effect on flowering in rice, a short-day plant.
Here, we revealed that NB by red light pulse (RL) in the mid-night suppresses Ehd1 in morning. In addition, Ehd1, a Hd3a inducer, was induced by blue light (BL). We also found that Lhd4/Ghd7, a floral repressor, was induced by RL at the NBmax. Consistently, Lhd4/Ghd7 expression in mid-morning under LD required phytochromes. Therefore, Lhd4/Ghd7 may be involved in the NB suppression of flowering. Furthermore, RL effects at NBmax following BL with a certain time lag to suppress BL-induction of Ehd1, suggested an effective period after RL for Lhd4/Ghd7-mediated suppression of BL-induction of Ehd1. Taken together, we discuss the relevance on molecular mechanisms for photoperiodic flowering and NB floral suppression in rice.
