Calcium-dependent and independent phospho-control of plant immunity by integrating kinase signalling with transcriptional regulation.

通过整合激酶信号传导与转录调控，对植物免疫进行钙依赖性和独立的磷酸控制。

• 批准号: 468855488
• 负责人: Dr. Justin Lee
• 金额: --
• 依托单位: National Natural Science Foundation of China
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/468855488?language=en
• 关键词: Calcium; dependent; independent; phospho; control

Plant immunity is a continuum of varying resistance intensities, spreading from local infection sites to distal tissues, which is augmented by effector-triggered immunity (ETI, i.e. the ability to recognize pathogen effectors) and autoimmunity (typically resulting from loss of an effector target). The Arabidopsis thaliana calcium-dependent protein kinase (CDPK), CPK5, is a highly calcium sensitive signalling hub in plant immunity. It controls immune responses at the plasma membrane (PM) via direct phosphorylation of the NADPH-oxidase RBOHD for ROS production and phosphorylation of EXO70B1 to modulate exocyst function in the transport of key PM immune components. In a collaborative effort, the Tang and Romeis groups could show that CPK5, but not other CDPK isoforms, is required for exo70B1-activated and TN2-dependent autoimmunity. Additionally, CPK5 signalling triggers transcription-based resistance leading to systemic immunity (via SARD1 and CAMTA3 transcription factors). Comparative in vivo phosphoproteomics analysis of cpk5 mutant lines identified defence-related transcriptional regulator CAMTA3 as well as MAPK-signalling cascade components as potential CPK5 substrate proteins. Joint experiments verify that CPK5 phosphorylates CAMTA3 directly, and both proteins co-localize in the plant nucleus. Furthermore, enhanced disease resistance to powdery mildew, reported for CPK5-OE lines and for exo70B1 mutants, is compromised in the presence of the dominant camta3-3D (A855V) allele. These data are consistent with the reported CAMTA3 function as a negative transcriptional regulator of plant immunity; as validated by the Lee group recently, CAMTA3 nuclear localization and protein stability is controlled by phosphorylation through MAPKs. In this joint proposal, we will synergize our efforts to investigate:(i) EXO70B-mediated transport of immune components at the PM in dependency of CPK5. (ii) Dual control of nuclear negative immune regulator CAMTA3 by dynamic phosphorylation through CPK5 and MAPKs. (iii) Mechanistic basis for CPK5 enzyme location and shuffling between the PM and the nucleus. (iv) Cross-interference between CDPK and MAPK signalling in local signal initiation to long-term systemic defence manifestationGiven the detailed biochemical, molecular, and genetic characterization of the immune components investigated, and the broad technical expertise spanning from genetics to in vivo phosphoproteomics, this proposal provides a unique opportunity to uncover underlying mechanisms of long discussed regulatory principles prevalent to (but not only) immune signalling – that is the interplay of pathways (CDPK/MAPK cascades), the dynamic modulation of multiple post-translational modifications converging on a common key regulatory substrate (e.g. CAMTA3), and the role of subcellular re-distribution of signalling components - facilitating an unpreceded resolution on the molecular level.

植物免疫是不同抵抗强度的连续体，从局部感染部位传播到远端组织，通过效应物触发的免疫（ETI，即识别病原体效应物的能力）和自身免疫（通常是由于效应物靶标的丢失而导致）增强。拟南芥钙依赖性蛋白激酶 (CDPK) CPK5 是植物免疫中高度钙敏感的信号中枢。它通过直接磷酸化 NADPH 氧化酶 RBOHD 来产生 ROS，以及磷酸化 EXO70B1 来调节质膜 (PM) 关键 PM 免疫成分运输中的外囊功能，从而控制质膜 (PM) 的免疫反应。通过合作，Tang 和 Romeis 小组证明，exo70B1 激活和 TN2 依赖性自身免疫需要 CPK5，而不是其他 CDPK 亚型。此外，CPK5 信号传导会触发基于转录的抗性，从而产生系统免疫（通过 SARD1 和 CAMTA3 转录因子）。 cpk5 突变体系的比较体内磷酸蛋白质组学分析确定了防御相关转录调节因子 CAMTA3 以及 MAPK 信号级联成分作为潜在的 CPK5 底物蛋白。联合实验验证了 CPK5 直接磷酸化 CAMTA3，并且两种蛋白在植物核中共定位。此外，据报道，CPK5-OE 品系和 exo70B1 突变体对白粉病的抗病性增强，但在显性 camta3-3D (A855V) 等位基因的存在下会受到损害。这些数据与报道的 CAMTA3 作为植物免疫负转录调节因子的功能一致； Lee 小组最近证实，CAMTA3 核定位和蛋白质稳定性是通过 MAPK 磷酸化控制的。在这项联合提案中，我们将协同努力研究：(i) EXO70B 介导的 PM 上依赖于 CPK5 的免疫成分转运。 (ii) 通过 CPK5 和 MAPK 的动态磷酸化对核负免疫调节因子 CAMTA3 进行双重控制。 (iii) CPK5 酶在 PM 和细胞核之间定位和改组的机制基础。 (iv) CDPK 和 MAPK 信号传导在局部信号启动到长期系统防御表现中的交叉干扰鉴于所研究的免疫成分的详细生化、分子和遗传特征，以及从遗传学到体内磷酸蛋白质组学的广泛技术专业知识，该提案提供了一个独特的机会来揭示长期讨论的普遍存在的监管原则的潜在机制（但不是 仅）免疫信号传导——即通路的相互作用（CDPK/MAPK级联）、汇聚在共同关键调节底物（例如CAMTA3）上的多个翻译后修饰的动态调节，以及信号成分的亚细胞重新分布的作用——促进分子水平上前所未有的解决方案。