Brassinosteroid-Activated BRI1-EMS-SUPPRESSOR 1 Inhibits Flavonoid Biosynthesis and Coordinates Growth and UV-B Stress Responses in Plants
Brassinosteroid-Activated BRI1-EMS-SUPPRESSOR 1 Inhibits Flavonoid Biosynthesis and Coordinates Growth and UV-B Stress Responses in Plants
复制标题
油菜素类固醇激活的 BRI1-EMS-SUPPRESSOR 1 抑制类黄酮生物合成并协调植物的生长和 UV-B 胁迫反应
DOI：
10.1105/tpc.20.00048
复制
发表时间：
2020-10-01
期刊：
影响因子：
11.6
通讯作者：
Liu, Hongtao
中科院分区：
文献类型：
--
作者：
Liang, Tong;Shi, Chen;Liu, Hongtao
BES 1是油菜素内酯信号转导的关键转录因子，通过调节黄酮醇的生物合成来协调植物在不断变化的UV-B条件下的生长和胁迫响应。UV-B光是一种潜在的胁迫因子，但植物如何协调生长和UV-B胁迫反应还没有很好的了解。在这里，我们报告油菜素类固醇（BR）信号抑制UV-B胁迫反应在拟南芥（拟南芥）和各种作物通过控制黄酮醇的生物合成。我们进一步证明了BRI 1-EMS-SUPPLYOR 1（BES 1）介导植物生长和UV-B防御反应之间的权衡。BES 1是参与BR信号传导的主转录因子，抑制转录因子基因MYB 11、MYB 12和MYB 111的表达，这些基因激活黄酮醇生物合成。BES 1以BR增强的方式直接结合这些MYB的启动子，以抑制它们的表达，从而减少黄酮醇的积累。然而，暴露于宽带UV-B下调BES 1的表达，从而促进黄酮醇积累。这些发现表明BR激活的BES 1不仅促进生长，而且抑制类黄酮的生物合成。UV-B胁迫抑制BES 1的表达，将能量分配给类黄酮生物合成和UV-B胁迫响应，使植物能够及时从生长转换到UV-B胁迫响应。
BES1, a key transcription factor involved in brassinosteroid signaling, coordinates plant growth and stress responses under ever-changing UV-B conditions by modulating flavonol biosynthesis. UV-B light is a potential stress factor in plants, but how plants coordinate growth and UV-B stress responses is not well understood. Here, we report that brassinosteroid (BR) signaling inhibits UV-B stress responses in Arabidopsis (Arabidopsis thaliana) and various crops by controlling flavonol biosynthesis. We further demonstrate that BRI1-EMS-SUPPRESSOR 1 (BES1) mediates the tradeoff between plant growth and UV-B defense responses. BES1, a master transcription factor involved in BR signaling, represses the expression of transcription factor genes MYB11, MYB12, and MYB111, which activate flavonol biosynthesis. BES1 directly binds to the promoters of these MYBs in a BR-enhanced manner to repress their expression, thereby reducing flavonol accumulation. However, exposure to broadband UV-B down-regulates BES1 expression, thus promoting flavonol accumulation. These findings demonstrate that BR-activated BES1 not only promotes growth but also inhibits flavonoid biosynthesis. UV-B stress suppresses the expression of BES1 to allocate energy to flavonoid biosynthesis and UV-B stress responses, allowing plants to switch from growth to UV-B stress responses in a timely manner.