Lee Jae-Hyung, Park Chung-Mo
a Department of Chemistry ; Seoul National University , Seoul , Korea.
b Plant Genomics and Breeding Institute; Seoul National University ; Seoul , Korea.
Plant Signal Behav. 2015;10(11):e1089373. doi: 10.1080/15592324.2015.1089373.
Appropriate timing of flowering is critical for propagation and reproductive success in plants. Therefore, flowering time is coordinately regulated by endogenous developmental programs and external signals, such as changes in photoperiod and temperature. Flowering is delayed by a transient shift to cold temperatures that frequently occurs during early spring in the temperate zones. It is known that the delayed flowering by short-term cold stress is mediated primarily by the floral repressor FLOWERING LOCUS C (FLC). However, how the FLC-mediated cold signals are integrated into flowering genetic pathways is not fully understood. We have recently reported that the INDUCER OF CBF EXPRESSION 1 (ICE1), which is a master regulator of cold responses, FLC, and the floral integrator SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) constitute an elaborated feedforward-feedback loop that integrates photoperiod and cold temperature signals to regulate seasonal flowering in Arabidopsis. Cold temperatures promote the binding of ICE1 to FLC promoter to induce its expression, resulting in delayed flowering. However, under floral inductive conditions, SOC1 induces flowering by blocking the ICE1 activity. We propose that the ICE1-FLC-SOC1 signaling network fine-tunes the timing of photoperiodic flowering during changing seasons.
花期的适时调控对于植物的繁殖和生殖成功至关重要。因此，开花时间受内源发育程序和外部信号（如光周期和温度变化）的协同调控。在温带地区，早春时常出现的短暂低温会延迟开花。已知短期冷胁迫导致的开花延迟主要由开花抑制因子开花位点C（FLC）介导。然而，FLC介导的冷信号如何整合到开花遗传途径中尚不完全清楚。我们最近报道，CBF表达诱导因子1（ICE1）作为冷反应、FLC的主要调节因子以及开花整合因子CONSTANS过表达抑制因子1（SOC1），构成了一个精细的前馈-反馈环，该环整合光周期和低温信号以调控拟南芥的季节性开花。低温促进ICE1与FLC启动子结合以诱导其表达，从而导致开花延迟。然而，在开花诱导条件下，SOC1通过阻断ICE1活性来诱导开花。我们提出，ICE1-FLC-SOC1信号网络在季节变化期间微调光周期开花的时间。
