A flagellin-induced complex of the receptor FLS2 and BAK1 initiates plant defence
A flagellin-induced complex of the receptor FLS2 and BAK1 initiates plant defence
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DOI：
10.1038/nature05999
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发表时间：
2007-07-26
期刊：
影响因子：
64.8
通讯作者：
Boller, Thomas
中科院分区：
文献类型：
--
作者：
Chinchilla, Delphine;Zipfel, Cyril;Boller, Thomas
植物通过使用模式识别受体识别病原体相关分子模式（PAMP）来感知潜在的微生物入侵者（1）。在拟南芥中，富含亮氨酸的重复序列受体激酶鞭毛蛋白敏感性2（FLS 2）（参考文献2）和延伸因子Tu受体（参考文献3）作为细菌PAMPs鞭毛蛋白（4）和延伸因子Tu（EF-Tu）（参考文献5）的模式识别受体，并有助于抵抗细菌病原体。关于受体激活与细胞内信号转导之间的分子机制知之甚少。在这里，我们表明BAK 1（BRI 1相关受体激酶1），一种富含亮氨酸的重复受体样激酶，据报道可调节油菜素类固醇受体BRI 1（参考文献6，7），参与FLS 2和EFR的信号传导。携带bak 1突变的植物表现出正常的鞭毛蛋白结合，但异常的早期和晚期鞭毛蛋白触发的反应，表明BAK 1作为一个积极的调节信号。bak 1突变体植物也表现出早期减少，但不是晚期，EF-Tu触发的反应。对PAMP反应的降低并不是因为对油菜素类固醇敏感性的降低。我们提供的证据表明，FLS 2和BAK 1在体内形成一个复合物，在一个特定的配体依赖性的方式，在第一分钟的刺激与鞭毛蛋白。因此，BAK 1不仅通过植物激素受体BRI 1与发育调节相关（参考文献6、7），而且在启动先天免疫的PRR依赖性信号传导中具有功能作用。
Plants sense potential microbial invaders by using pattern-recognition receptors to recognize pathogen-associated molecular patterns (PAMPs)(1). In Arabidopsis thaliana, the leucine-rich repeat receptor kinases flagellin-sensitive 2 (FLS2) (ref. 2) and elongation factor Tu receptor (EFR) ( ref. 3) act as pattern-recognition receptors for the bacterial PAMPs flagellin(4) and elongation factor Tu (EF-Tu) ( ref. 5) and contribute to resistance against bacterial pathogens. Little is known about the molecular mechanisms that link receptor activation to intracellular signal transduction. Here we show that BAK1 (BRI1-associated receptor kinase 1), a leucine-rich repeat receptor-like kinase that has been reported to regulate the brassinosteroid receptor BRI1 (refs 6,7), is involved in signalling by FLS2 and EFR. Plants carrying bak1 mutations show normal flagellin binding but abnormal early and late flagellin-triggered responses, indicating that BAK1 acts as a positive regulator in signalling. The bak1-mutant plants also show a reduction in early, but not late, EF-Tu-triggered responses. The decrease in responses to PAMPs is not due to reduced sensitivity to brassino-steroids. We provide evidence that FLS2 and BAK1 form a complex in vivo, in a specific ligand-dependent manner, within the first minutes of stimulation with flagellin. Thus, BAK1 is not only associated with developmental regulation through the plant hormone receptor BRI1 ( refs 6,7), but also has a functional role in PRR-dependent signalling, which initiates innate immunity.