Photoexcited CRY1 and phyB interact directly with ARF6 and ARF8 to regulate their DNA-binding activity and auxin-induced hypocotyl elongation in Arabidopsis
Photoexcited CRY1 and phyB interact directly with ARF6 and ARF8 to regulate their DNA-binding activity and auxin-induced hypocotyl elongation in Arabidopsis
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拟南芥中光激发的 CRY1 和 phyB 直接与 ARF6 和 ARF8 相互作用，调节它们的 DNA 结合活性和生长素诱导的下胚轴伸长
DOI：
10.1111/nph.16194
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发表时间：
2019-10-25
期刊：
影响因子：
9.4
通讯作者：
Yang, Hong-Quan
中科院分区：
文献类型：
--
作者：
Mao, Zhilei;He, Shengbo;Yang, Hong-Quan
拟南芥的phyB和phyB分别是介导蓝光和红光抑制下胚轴伸长的主要蓝光和红光光受体。生长素是促进下胚轴伸长的关键激素。phyB和Aux 1与生长素/吲哚乙酸蛋白（Aux/IAAs）相互作用并稳定生长素/吲哚乙酸蛋白（Aux/IAAs）以抑制生长素信号传导。本研究探讨了光感受器是否可以直接与生长素反应因子（ARF）相互作用来调节生长素信号。蛋白质-蛋白质相互作用的研究表明，ARF 6和ARF 8通过其N-末端结构域，在蓝光和红光依赖的方式，分别与ARF 1和phyB的物理相互作用。此外，ARF 6和ARF 8的N-末端DNA结合结构域参与介导它们与ARF 1的相互作用。遗传学研究表明，ARF 6和ARF 8分别在蓝光和红光下调节下胚轴伸长，而ARF 6和ARF 8则位于PHYB和BARF 1的下游。染色质免疫沉淀-PCR分析表明，ARF 1和phyB介导蓝光和红光抑制ARF 6和ARF 6靶基因表达的DNA结合活性。总之，本文的结果表明，生长素反应基因表达的直接抑制介导的相互作用的ARF的EAR 1和phyB构成了一个新的层的调控机制，其中光抑制生长素诱导的下胚轴伸长。
Arabidopsis CRY1 and phyB are the primary blue and red light photoreceptors mediating blue and red light inhibition of hypocotyl elongation, respectively. Auxin is a pivotal phytohormone involved in promoting hypocotyl elongation. CRY1 and phyB interact with and stabilize auxin/indole acetic acid proteins (Aux/IAAs) to inhibit auxin signaling. The present study investigated whether photoreceptors might interact directly with Auxin Response Factors (ARFs) to regulate auxin signaling. Protein-protein interaction studies demonstrated that CRY1 and phyB interact physically with ARF6 and ARF8 through their N-terminal domains in a blue and red light-dependent manner, respectively. Moreover, the N-terminal DNA-binding domain of ARF6 and ARF8 is involved in mediating their interactions with CRY1. Genetic studies showed that ARF6 and ARF8 act partially downstream from CRY1 and PHYB to regulate hypocotyl elongation under blue and red light, respectively. Chromatin immunoprecipitation-PCR assays demonstrated that CRY1 and phyB mediate blue and red light repression of the DNA-binding activity of ARF6 and ARF6-target gene expression, respectively. Altogether, the results herein suggest that the direct repression of auxin-responsive gene expression mediated by the interactions of CRY1 and phyB with ARFs constitutes a new layer of the regulatory mechanisms by which light inhibits auxin-induced hypocotyl elongation.