Abstract
Plants are classified into short-day plants (SDP) and long-day plants (LDP) based on their flowering response to day-length. Recently, signaling cascades of flowering have been intensively studied. Analysis of flowering-time genes in Arabidopsis (LDP) and rice (SDP) suggests genes controling photoperiodic flowering are conserved between them. To investigate the molecular mechanisms of rice flowering, we employed the night break (NB) experiment.
We found that Hd3a mRNA was dramatically suppressed by a single NB without affecting OsGI and Hd1 expression. Suppression of Hd3a by NB is highest in the middle of night and recovers next day with SD treatment. NB treated on se5 mutants, defected on the phytochrome pathway, exhibited no suppression of Hd3a, indicating Se5 is essential for NB effect. However, which phytochrome plays a role in NB is not known. We are investigating the effects of phytochromes on the photoperiodic flowering in rice by using phytochrome mutants.
