Cyclic nucleotide-gated ion channel (CNGC)-mediated signal transduction and hormonal crosstalk in plant natural immunity

植物天然免疫中环核苷酸门控离子通道（CNGC）介导的信号转导和激素串扰

• 批准号: RGPIN-2014-04114
• 负责人: Yoshioka, Keiko
• 金额: $ 2.91万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=669372
• 关键词: Cyclic; nucleotide; gated; ion; channel

BACKGROUND:*Due to global population growth, increasing food production is an urgent issue in the world. However, significant amounts of agricultural products are lost annually due to plant disease in spite of the extensive usage of agrochemicals that may harm the environment. Thus, the understanding of plant immunity and finding ways to enhance natural resistance of plans is the key for security of food production and a healthy environment in the future. *To date, we have shown that the cyclic nucleotide-gated ion channels CNGC11 and 12 play significant roles in plant immunity and we have analyzed their structure-function relationships. We also used a CNGC mutant to examine signal crosstalk. In animals, CNGCs affect visual and olfactory signal transduction and are regulated by the calcium sensor protein calmodulin (CaM). However, in plants, the regulators of CNGCs and their downstream signal transduction cascades remain largely unknown. **RESEARCH OBJECTIVE AND OUTLINE:*The long-term goal of my research is to understand the signal transduction pathways and networks integrating environmental stresses with pathogen infection at the molecular level. To this aim, over the next 5 years we will: I) Identify and characterize components of CNGC-mediated signal transduction, II) Investigate the regulation of CNGCs, and III) Investigate hormonal crosstalk and environmental effects on plant immunity.*For aim I, we identified rdd1, a suppressor of the CNGC2 null mutant dnd1 (defense no death1), which displays an autoimmune phenotype. Thus, RDD1 likely acts downstream of CNGC2-mediated disease resistance signaling or on a signaling cascade that affects CNGC2 signaling. The proposed work will investigate the involvement of RDD1 in CNGC-mediated resistance signaling at the molecular level. Furthermore, we identified five additional suppressors, which we will characterize and identify. *Aim II addresses regulation of CNGCs by CaM. Animal CNGC research showed that CaM binding negatively regulates CNGCs; however, the regulation of plant CNGCs by CaM remains unclear. In this proposal, we will determine the CaM binding domains in plant CNGCs and characterize their binding kinetics upon pathogen infection.*Aim III addresses the crosstalk between salicylic acid (SA), abscisic acid (ABA) and auxin. SA is a key signaling molecule in plant immunity and the complex crosstalk among SA, ABA and auxin strongly influences disease resistance. This suggests a coordinated signaling network allowing plants to allocate resources to fight pathogens, respond to abiotic stresses and maintain growth. In addition, our current data indicate that environmental factors affect CNGC signaling. To identify the key nodes in this crosstalk, we conducted a yeast two-hybrid analysis of ABA- and SA-inducible proteins and discovered several candidate interactions that may mediate crosstalk. In this proposal, we will analyze molecular mechanisms of these candidates and conduct another interactome analysis between SA and auxin signaling components.**PREDICTED SIGNIFICANCE:*The outcome of this proposal will significantly contribute to our understanding of CNGC-mediated plant immune responses. Furthermore, hormonal crosstalk in plant immunity has emerged as an important topic, since it is related to environmental conditions. Currently, plant diseases cause significant annual losses of agricultural products, despite the extensive use of costly agro-chemicals. In addition, unstable climate conditions may increase the frequency of disease outbreaks. Thus, the proposed program will significantly impact agricultural research to improve plant disease resistance for a sustainable human society.

背景：* 由于全球人口增长，增加粮食生产是世界上一个紧迫的问题。然而，尽管广泛使用可能损害环境的农用化学品，但每年由于植物病害而损失大量农产品。因此，了解植物的免疫力，寻找提高植物天然抗性的方法，是未来粮食生产安全和健康环境的关键。* 迄今为止，我们已经证明了环核苷酸门控离子通道CNGC 11和12在植物免疫中发挥重要作用，并分析了它们的结构-功能关系。我们还使用CNGC突变体来检查信号串扰。在动物中，CNGC影响视觉和嗅觉信号转导，并受钙传感器蛋白钙调素（CaM）的调节。然而，在植物中，CNGCs的调节剂及其下游信号转导级联在很大程度上仍然未知。** 研究目标和概述：* 我的研究的长期目标是在分子水平上了解整合环境压力和病原体感染的信号转导途径和网络。为了实现这一目标，在接下来的5年里，我们将：I）鉴定和表征CNGC介导的信号转导的组分，II）研究CNGC的调节，III）研究激素串扰和环境对植物免疫的影响。对于目标I，我们确定了rdd 1，CNGC 2无效突变体dnd 1（防御无死亡1）的抑制因子，其显示自身免疫表型。因此，RDD 1可能作用于CNGC 2介导的抗病信号传导的下游或影响CNGC 2信号传导的信号级联。拟议的工作将在分子水平上研究RDD 1参与CNGC介导的抗性信号传导。此外，我们确定了另外五个抑制因子，我们将对其进行表征和识别。* 目标II涉及CaM对CNGC的监管。动物CNGC研究表明，CaM结合负调控CNGC;然而，CaM对植物CNGC的调控尚不清楚。在这个提议中，我们将确定植物CNGC中的CaM结合结构域，并表征病原体感染后它们的结合动力学。目的III研究水杨酸（SA）、脱落酸（阿坝）和生长素之间的串扰。SA是植物免疫的关键信号分子，SA、阿坝和生长素之间的复杂串扰对植物的抗病性有重要影响。这表明一个协调的信号网络允许植物分配资源以对抗病原体，应对非生物胁迫并保持生长。此外，我们目前的数据表明，环境因素影响CNGC信号传导。为了确定在这个串扰的关键节点，我们进行了酵母双杂交分析阿坝和SA诱导蛋白，并发现了几个候选的相互作用，可能介导的串扰。在这个提议中，我们将分析这些候选者的分子机制，并进行SA和生长素信号组分之间的另一个相互作用组分析。预测的意义：* 本提案的结果将大大有助于我们对CNGC介导的植物免疫反应的理解。此外，植物免疫中的激素串扰已经成为一个重要的课题，因为它与环境条件有关。目前，尽管广泛使用昂贵的农用化学品，但植物病害每年造成农产品的重大损失。此外，不稳定的气候条件可能会增加疾病爆发的频率。因此，拟议的计划将对农业研究产生重大影响，以提高植物抗病性，促进人类社会的可持续发展。