Circadian Evening Complex Represses Jasmonate-Induced Leaf Senescence in Arabidopsis
Circadian Evening Complex Represses Jasmonate-Induced Leaf Senescence in Arabidopsis
复制标题
昼夜节律复合物抑制拟南芥茉莉酸诱导的叶片衰老
DOI：
10.1016/j.molp.2017.12.017
复制
发表时间：
2018-02-05
期刊：
影响因子：
27.5
通讯作者：
Wang, Lei
中科院分区：
文献类型：
--
作者：
Zhang, Yuanyuan;Wang, Yan;Wang, Lei
植物启动叶片衰老是为了在生长季节结束或在压力下将老化的能量和营养物质重新分配给发育中的组织，以优化生长适应性和繁殖。茉莉酸盐（Jasmonate， JA）是一种脂源性植物激素，是诱导叶片衰老的重要内源信号。然而，昼夜节律时钟是否以及如何开启JA信号诱导植物叶片衰老仍然是一个谜。在这项研究中，我们发现夜间复合体（EC）是昼夜节律振荡器的核心组成部分，对拟南芥叶片衰老具有负向调控作用。转录组学分析表明，EC与JA信号和响应密切相关，这与EC突变体在JA诱导下一致表现出的加速叶片衰老一致。我们发现EC直接结合MYC2的启动子，并抑制其表达，MYC2编码ja诱导叶片衰老的关键激活因子。遗传分析进一步表明，ja对EC突变体叶片衰老的加速作用被myc2、myc3、myc4三重突变所抵消。总的来说，这些结果揭示了一个关键的分子机制，说明了昼夜时钟的核心成分是如何调节JA信号来调节叶片衰老的。
Plants initiate leaf senescence to reallocate energy and nutrients from aging to developing tissues for optimizing growth fitness and reproduction at the end of the growing season or under stress. Jasmonate (JA), a lipid-derived phytohormone, is known as an important endogenous signal in inducing leaf senescence. However, whether and how the circadian clock gates JA signaling to induce leaf senescence in plants remains elusive. In this study, we show that Evening Complex (EC), a core component of the circadian oscillator, negatively regulates leaf senescence in Arabidopsis thaliana. Transcriptomic profiling analysis reveals that EC is closely involved in JA signaling and response, consistent with accelerated leaf senescence unanimously displayed by EC mutants upon JA induction. We found that EC directly binds the promoter of MYC2, which encodes a key activator of JA-induced leaf senescence, and represses its expression. Genetic analysis further demonstrated that the accelerated JA-induced leaf senescence in EC mutants is abrogated by myc2 myc3 myc4 triple mutation. Collectively, these results reveal a critical molecular mechanism illustrating how the core component of the circadian clock gates JA signaling to regulate leaf senescence.