作物的地理分布主要取决于光周期调控的开花时间差异，因此光周期调控开花启始对农业生产至关重要。蓝光信号及蓝光受体隐花素CRY2在光周期诱导开花启始中具有关键作用。油菜素甾醇(BR)是一类广泛存在于植物中的甾醇类激素，调控植物生长发育过程，已知BR可通过自主途径调控开花时间，但BR是否参与光周期途径未见报道。我们最近的研究发现光周期可以部分补偿BR受体缺失造成的晚花表型，而BR信号转导中的关键转录因子BES1及BEE1都参与光周期诱导开花启始调控。本项目拟深入研究外源光信号和内源BR信号协同调控光周期诱导开花时间的分子及生化机制。将研究BES1和BEE1调控光周期诱导开花时间的具体机制；探究蓝光及CRY2与BES1及BEE1的相互关系；发掘新的受蓝光和BR共同调控的基因并探索其功能。最终解决BR在光周期诱导开花启始中的功能，以及光信号与油菜素甾醇如何协同调控光周期诱导开花启始的关键科学问题。

The geographical distribution of crops mainly depends on the Photoperiodic flowering, so photoperiodic flowering is very important for the agricultural production. Blue light signal and blue light photoreceptor CRY2 are key components of photoperiodic flowering. Brassinosteriodis (BRs) are a class of steroidal hormones essential for plant growth and development, it is reported before that BR signaling regulated flowering through autonomous pathway. However, whether BR is involved in photoperiodic flowering is unknown. It is of great theoretical and practical significance to study how BR is involved in the photoperiodic flowering. Our recent results indicate that photoperiod pathway can partially complement the late flowering phenotype of bri1, and the two key transcription factors of BR signaling, BES1 and BEE1 are both involved in photoperiodic flowering. In this project we will study how external light signal coordinates with internal BR signal to regulate photoperiodic flowering. We will study the mechanisms of BES1 and BEE1 regulated photoperiodic flowering, the relationship of CRY2 and BES1 or BEE1, and will also try to find new genes that are regulated by both blue light and BR. We will figure out the function of BR in the photoperiodic flowering, and also how light and BR coordinate to regulate photoperiodic flowering.