The Arabidopsis DELLA RGA-LIKE3 Is a Direct Target of MYC2 and Modulates Jasmonate Signaling Responses[C][W]
The Arabidopsis DELLA RGA-LIKE3 Is a Direct Target of MYC2 and Modulates Jasmonate Signaling Responses[C][W]
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DOI：
10.1105/tpc.112.101428
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发表时间：
2012-08
期刊：
影响因子：
11.6
通讯作者：
Michael Wild;J. Davière;Soizic Cheminant;T. Regnault;N. Baumberger;D. Heintz;R. Baltz;P. Genschik-P.-Gensch
中科院分区：
文献类型：
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作者：
Michael Wild;J. Davière;Soizic Cheminant;T. Regnault;N. Baumberger;D. Heintz;R. Baltz;P. Genschik-P.-Gensch
DELLA蛋白作为赤霉素（GA）信号通路的负调控因子发挥作用。本文报道RGL3是一种独特的DELLA蛋白，它作为一种整合因子，将赤霉素和茉莉酸信号联系起来，从而能够对植物的抗病性进行适应性调节。赤霉素（GAs）是植物激素，参与响应内源和环境信号对植物生长的调节。赤霉素通过刺激抑制生长的核DELLA蛋白的降解来促进生长。在拟南芥中，DELLA由一个包含五种蛋白质的小家族组成，这些蛋白质在抑制赤霉素反应方面具有独特但也有重叠的功能。这项研究表明，DELLA蛋白RGA - LIKE3（RGL3）对于充分增强茉莉酸（JA）介导的反应至关重要。我们发现茉莉酸以依赖于冠菌素不敏感1（COI1）和茉莉酸不敏感1（JIN1/MYC2）的方式快速诱导RGL3的表达。此外，我们证明MYC2直接与RGL3启动子结合。而且，我们发现RGL3（与其他DELLA蛋白一样）与茉莉酸ZIM结构域（JAZ）蛋白相互作用，JAZ蛋白是茉莉酸信号的关键抑制因子。这些发现表明，依赖于茉莉酸/ MYC2的RGL3积累抑制了JAZ的活性，进而增强了茉莉酸响应基因的表达。相应地，我们发现初级茉莉酸响应基因的诱导在rgl3 - 5突变体中减少，而在过表达RGL3的转基因植株中增强。因此，RGL3正向调节茉莉酸介导的对死体营养型病原菌灰葡萄孢的抗性以及对半活体营养型病原菌丁香假单胞菌的感病性。我们提出茉莉酸介导的RGL3表达诱导具有适应性意义，可能代表了DELLA蛋白近期的功能多样化。
The DELLA proteins function as negative regulators of the gibberellin (GA) signaling pathway. This article reports that RGL3 is a distinct DELLA protein that acts as an integrating factor that links GA and jasmonate signaling to enable adaptive regulation of plant resistance to pathogens. Gibberellins (GAs) are plant hormones involved in the regulation of plant growth in response to endogenous and environmental signals. GA promotes growth by stimulating the degradation of nuclear growth–repressing DELLA proteins. In Arabidopsis thaliana, DELLAs consist of a small family of five proteins that display distinct but also overlapping functions in repressing GA responses. This study reveals that DELLA RGA-LIKE3 (RGL3) protein is essential to fully enhance the jasmonate (JA)-mediated responses. We show that JA rapidly induces RGL3 expression in a CORONATINE INSENSITIVE1 (COI1)– and JASMONATE INSENSITIVE1 (JIN1/MYC2)–dependent manner. In addition, we demonstrate that MYC2 binds directly to RGL3 promoter. Furthermore, we show that RGL3 (like the other DELLAs) interacts with JA ZIM-domain (JAZ) proteins, key repressors of JA signaling. These findings suggest that JA/MYC2-dependent accumulation of RGL3 represses JAZ activity, which in turn enhances the expression of JA-responsive genes. Accordingly, we show that induction of primary JA-responsive genes is reduced in the rgl3-5 mutant and enhanced in transgenic lines overexpressing RGL3. Hence, RGL3 positively regulates JA-mediated resistance to the necrotroph Botrytis cinerea and susceptibility to the hemibiotroph Pseudomonas syringae. We propose that JA-mediated induction of RGL3 expression is of adaptive significance and might represent a recent functional diversification of the DELLAs.