Strigolactones (SLs) are hormones essential for plant development and environmental responses. SL perception requires the formation of the complex composed of an SL receptor DWARF14 (D14), F-box protein D3, and transcriptional repressor D53, triggering ubiquitination and degradation of D53 to activate signal transduction. However, mechanisms of SL perception and their influence on plant architecture and environmental responses remain elusive and controversial. Here, we report that key residues at interfaces of the AtD14-D3-ASK1 complex are essential for the activation of SL perception, discover that overexpression of the D3-CTH motif negatively regulates SL perception to enhance tillering, and reveal the importance of phosphorylation and N-terminal disordered (NTD) domain in mediating ubiquitination and degradation of D14. Importantly, low nitrogen promotes phosphorylation and stabilization of D14 to repress rice tillering. These findings reveal a panorama of the activation, termination, and regulation of SL perception, which determines the plasticity of plant architecture in complex environments.

中文翻译：

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水稻中独脚金内酯感知的调控机制


独脚金内酯 （SLs） 是植物发育和环境反应所必需的激素。SL 感知需要形成由 SL 受体 DWARF14 （D14）、F-box 蛋白 D3 和转录抑制因子 D53 组成的复合物，触发 D53 的泛素化和降解以激活信号转导。然而，SL 感知机制及其对植物结构和环境响应的影响仍然难以捉摸且存在争议。在这里，我们报道了 AtD14-D3-ASK1 复合物界面上的关键残基对 SL 感知的激活至关重要，发现 D3-CTH 基序的过表达负向调节 SL 感知以增强分蘖，并揭示了磷酸化和 N 末端无序 （NTD） 结构域在介导泛素化和降解中的重要性D14。重要的是，低氮促进 D14 的磷酸化和稳定化，从而抑制水稻分蘖。这些发现揭示了 SL 感知的激活、终止和调节的全景，这决定了复杂环境中植物结构的可塑性。