Mediator Subunit MED25 Physically Interacts with PHYTOCHROME INTERACTING FACTOR4 to Regulate Shade-Induced Hypocotyl Elongation in Tomato
Mediator Subunit MED25 Physically Interacts with PHYTOCHROME INTERACTING FACTOR4 to Regulate Shade-Induced Hypocotyl Elongation in Tomato
复制标题
介体亚基 MED25 与 PHYTOCHROME 相互作用因子 4 发生物理相互作用，调节番茄中遮荫诱导的下胚轴伸长
DOI：
10.1104/pp.20.00587
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发表时间：
2020
期刊：
影响因子：
7.4
通讯作者：
Li C
中科院分区：
文献类型：
--
作者：
Sun W;Han H;Deng L;Sun C;Xu Y;Lin L;Ren P;Zhao J;Zhai Q;Li C
遮荫触发重要的适应性反应，如遮荫-回避综合症，使植物能够对光合作用活性光的耗尽做出反应。碱性螺旋-环-螺旋转录因子光敏色素相互作用因子(PIF)通过调节多种植物激素的生物合成和细胞扩张相关基因的表达，在遮荫回避综合征网络中发挥关键作用。虽然已经在蛋白质水平上了解了PIF对遮荫反应的调控，但对依赖于PIF的遮荫反应基因的转录调控知之甚少。介体是一种进化上保守的转录共激活复合体，它将基因特异的转录因子与RNA聚合酶II(Pol II)机制连接起来，以调节基因的转录。在这里，我们报道了番茄(Solanum Lycopsicum)PIF4通过调节生长素生物合成和生长素信号蛋白的基因表达，在遮荫诱导下胚轴伸长过程中发挥重要作用。在这个过程中，介体亚单位25(MED25)与PIF4在PIF4靶基因的启动子区域发生物理相互作用，并招募Pol II来诱导基因转录。因此，MED25直接连接PIF4和POL II通用转录机制之间的通讯，以调节遮荫诱导的下胚轴伸长。总体而言，我们的结果揭示了MED25在遮荫下PIF4介导的转录调控中的一个新角色。
Shade triggers important adaptive responses such as the shade-avoidance syndrome, which enable plants to respond to the depletion of photosynthetically active light. The basic helix-loop-helix transcription factors PHYTOCHROME INTERACTING FACTORS (PIFs) play a key role in the shade-avoidance syndrome network by regulating the biosynthesis of multiple phytohormones and the expression of cell expansion-related genes. Although much has been learned about the regulation of PIFs in response to shade at the protein level, relatively little is known about the PIF-dependent transcriptional regulation of shade-responsive genes. Mediator is an evolutionarily conserved transcriptional coactivator complex that bridges gene-specific transcription factors with the RNA polymerase II (Pol II) machinery to regulate gene transcription. Here, we report that tomato (Solanum lycopersicum) PIF4 plays an important role in shade-induced hypocotyl elongation by regulating the expression of genes that encode auxin biosynthesis and auxin signaling proteins. During this process, Mediator subunit25 (MED25) physically interacts with PIF4 at the promoter regions of PIF4 target genes and also recruits Pol II to induce gene transcription. Thus, MED25 directly bridges the communication between PIF4 and Pol II general transcriptional machinery to regulate shade-induced hypocotyl elongation. Overall, our results reveal a novel role of MED25 in PIF4-mediated transcriptional regulation under shade.