Department of Biological Sciences, National University of Singapore, Singapore.
Dev Cell. 2010 Dec 14;19(6):884-94. doi: 10.1016/j.devcel.2010.10.024.
Gibberellins (GAs) modulate jasmonate (JA) signaling, which is essential for stress response and development in plants. However, the molecular details of such phytohormone interaction remain largely unknown. Here, we show that the JA ZIM-domain 1 (JAZ1) protein, a key repressor of JA signaling, interacts in vivo with DELLA proteins, repressors of the GA pathway. DELLAs prevent inhibitory JAZ1 interaction with a key transcriptional activator of JA responses, MYC2, and, thus, enhance the ability of MYC2 to regulate its target genes. Conversely, GA triggers degradation of DELLAs, which allows JAZ1 to bind MYC2 and suppress MYC2-dependent JA-signaling outputs. Therefore, our results reveal one means by which GAs suppress cellular competence to respond to JA. Because DELLAs serve as central regulators that mediate the crosstalk of various phytohormones, our model also suggests a candidate mechanism by which JA signaling may be fine-tuned by other signaling pathways through DELLAs.
赤霉素（GAs）调节茉莉酸（JA）信号，这对植物的应激反应和发育至关重要。然而，这种植物激素相互作用的分子细节在很大程度上仍然未知。在这里，我们表明，茉莉酸 ZIM 结构域 1（JAZ1）蛋白，JA 信号的关键抑制剂，与 DELLA 蛋白在体内相互作用，DELLA 蛋白是 GA 途径的抑制剂。DELLAs 阻止抑制性 JAZ1 与 JA 反应的关键转录激活因子 MYC2 的相互作用，从而增强 MYC2 调节其靶基因的能力。相反，GA 触发 DELLAs 的降解，这使得 JAZ1 能够与 MYC2 结合并抑制 MYC2 依赖的 JA 信号输出。因此，我们的结果揭示了 GAs 抑制细胞对 JA 反应能力的一种方式。因为 DELLAs 作为中央调节剂，介导各种植物激素的串扰，我们的模型还表明，JA 信号可能通过 DELLAs 被其他信号通路精细调节的候选机制。
