Plant Pattern-Recognition Receptor FLS2 Is Directed for Degradation by the Bacterial Ubiquitin Ligase AvrPtoB
Plant Pattern-Recognition Receptor FLS2 Is Directed for Degradation by the Bacterial Ubiquitin Ligase AvrPtoB
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DOI：
10.1016/j.cub.2008.10.063
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发表时间：
2008-12-09
期刊：
影响因子：
9.2
通讯作者：
Robatzek, Silke
中科院分区：
文献类型：
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作者：
Goehre, Vera;Spallek, Thomas;Robatzek, Silke
背景资料：植物主动防御的一个重要方面是检测由细胞表面受体介导的病原相关分子模式（PAMPs）。对于疾病的建立，病原体依赖于克服PAMP感知并使响应于PAMP而激活的植物信号传导途径失效的能力。因此，模式识别受体（PRR）是病原体效应物的主要靶标。FLS2，它的辅助受体BAK1，和EFR编码受体样激酶，发挥了作用，在免疫力对细菌pathogenes.Results：在这里，我们报告，在拟南芥中的假单胞菌pv番茄DC3000（PtoDC3000）的毒力是通过其效应AvrPtoB，促进降解FLS2的作用增强。我们表明，AvrPtoB，通过其N末端，与FLS2和BAK 1，其中与FLS2的相互作用增强flg22激活。在体外，AvrPtoB作为E3连接酶催化FLS2的激酶结构域的聚泛素化是有活性的，这是在植物中证实的过程。PtoDC3000毒力的充分增强似乎需要AvrPtoB的E3连接酶活性。结论：AvrPtoB，最初确定通过其激活的过敏性抗性在番茄品种中表达的Pto激酶，是由至少两个功能域：N端负责与Pto的相互作用，和C端进行E3连接酶活性。基于我们的研究结果，我们提出AvrPtoB的两个结构域共同作用，通过它们从细胞外周消除FLS2的能力来支持PtoDC3000在拟南芥中的毒力，并且可能还包括在病原体挑战后组成型表达或诱导的其他PAMP传感器。
Background: An important layer of active defense in plant immunity is the detection of pathogen-associated molecular patterns (PAMPs) mediated by cell-surface receptors. For the establishment of disease, pathogens depend on the ability to overcome PAMP perception and disable plant signaling pathways activated in response to PAMPs. Pattern recognition receptors (PRRs) are therefore prime targets for pathogen effectors. FLS2, its coreceptor BAK1, and EFR encode receptor-like kinases that play a role in immunity against bacterial pathogens.Results: Here, we report that virulence of Pseudomonas syringae pv tomato DC3000 (PtoDC3000) in Arabidopsis is enhanced through the action of its effector AvrPtoB, which promotes degradation of FLS2. We show that AvrPtoB, through its N terminus, associates with FLS2 and BAK1, of which interaction with FLS2 is enhanced by flg22 activation. In vitro, AvrPtoB is active as an E3 ligase to catalyze polyubiquitination of the kinase domain of FLS2, a process confirmed in planta. Full enhancement of PtoDC3000 virulence appears to require the E3 ligase activity of AvrPtoB.Conclusions: AvrPtoB, initially identified through its activation of hypersensitive resistance in tomato cultivars expressing the Pto kinase, is composed of at least two functional domains: the N terminus is responsible for interaction with Pto, and the C terminus carries an E3 ligase activity. Based on our findings, we propose that both domains of AvrPtoB act together to support the virulence of PtoDC3000 in Arabidopsis through their ability to eliminate FLS2 from the cell periphery, and probably also other PAMP sensors that are constitutively expressed or induced after pathogen challenge.