Cyclic nucleotide-gated ion channel (CNGC)-mediated signal transduction in plant stress responses

我们研究的长期目标是了解环核苷酸门控通道(CNGC)在植物胁迫反应中的信号转导，重点是免疫。CNGCs是植物中最大的阳离子通道家族之一，越来越多的证据表明，CNGCs通过其钙通道功能参与了多种生物现象，如免疫、向重力性、耐热性和花粉生长。CNGC被认为可以形成异构体，并与钙调蛋白等信号译码蛋白相互作用。*钙是真核信号通路中普遍存在的第二信使，控制着动物的肌肉收缩和神经元传递等许多现象。同样，钙离子在植物的信号转导中起着核心作用。植物细胞内钙离子的瞬时变化是由多种刺激引起的，如非生物胁迫(干旱、高温等)、生物胁迫(病原体侵染等)以及发育信号(生殖、根毛生长、生物钟)。要产生特定于刺激的信号以引起适当的反应，钙信号必须包含唯一的信息。然而，尽管钙信号很重要，但我们对刺激特异性钙信号产生的了解仍然有限。甚至植物中与胁迫相关的钙通道的识别仍然是个谜，因为在捕捉瞬时钙信号方面存在冗余和技术挑战。*在我们实验室，在前NSERC DG的支持下，我们发现CNGC是植物免疫中的关键角色，并报告了它们中的一些与钙信号密切相关。在接下来的五年里，我们将重点研究这三个方面：1.CNGC、钙和植物激素生长素的相互作用；2.CNGC相互作用和可能的信号复合体；3.利用遗传编码的钙传感器，CNGC介导的非生物和生物胁迫反应中的细胞内和细胞间钙信号。我们的过度假设是，CNGC在信号感知时与离子泵、受体和解码蛋白形成信号复合体，以产生刺激特异性的时间信号，以响应各种生物刺激。*钙信号在植物逆境反应中是至关重要的，然而，即使是基本的信息，如通道的类型，刺激物特异性的钙信号，以及许多下游信号成分的身份，都不清楚。这项拟议的项目旨在提供有关植物在胁迫感知中的钙信号的基本信息。此外，了解植物的胁迫反应对于可持续的粮食生产至关重要，特别是在当前不可预测的气候波动的情况下。我们的研究计划将揭示基本信息，以帮助开发保护植物免受各种胁迫的新方法。**

The long-term goal of our research is to understand cyclic nucleotide-gated channel (CNGC)-mediated signal transduction in plant stress responses, with an emphasis on immunity. CNGCs are one of the largest cation channel families in plants and accumulating evidence suggests their involvement in a wide variety of biological phenomena, such as immunity, gravitropism, thermo-tolerance, and pollen growth, through their calcium (Ca2+) channel function. CNGCs have been suggested to form heterotetramers and interact with signal decoder proteins, such as calmodulin. ***Ca2+ is a universal second messenger in the eukaryotic signaling pathways that control many phenomena, such as muscle contraction and neuronal transmission in animals. Similarly, Ca2+ plays a central role in signal transduction in plants. Transient changes in cytosolic Ca2+ levels ([Ca2+]cyt) in plants are rapidly induced by diverse stimuli such as abiotic stress (drought, heat, etc.), biotic stresses (pathogen infection, etc.), as well as developmental cues (reproduction, root hair growth, circadian clock). To generate stimulus-specific signals that elicit the appropriate responses, Ca2+ signals must contain unique information. However, despite the importance of Ca2+ signals, our understanding of the generation of stimulus-specific Ca2+ signals remains limited. Even the identity of stress-related Ca2+ channels in plants is still enigmatic due to redundancies and technical challenges in capturing transient Ca2+ signals. ***In our laboratory, with the support of the previous NSERC DG, we identified CNGCs as key players in plant immunity and have reported that some of them are tightly connected to Ca2+ signals. In the next five years, we will focus on these three aspects: 1. The interplay of CNGCs, Ca2+ and the plant hormone auxin, 2. CNGC interactors and possible signaling complexes and 3. CNGC-mediated intra- and inter-cellular Ca2+ signals in abiotic and biotic stress responses by utilizing genetically encoded Ca2+ sensors. Our overreaching hypothesis is that CNGCs form a signaling complex with ion pumps, receptors, and decoder proteins upon signal perception to generate stimulus-specific temporal signals in response to a wide variety of biological stimuli. ***Ca2+ signaling is paramount in plant stress responses, yet even fundamental information such as the types of channels, stimuli-specific Ca2+ signatures, and the identity of many downstream signaling components are not clear. The proposed project will aim to provide essential information on plant Ca2+ signaling upon stress perception. In addition, an understanding of plant stress responses is crucial for sustainable food production, especially with current unpredictable climate fluctuations. Our research program will reveal fundamental information to assist in the development of novel methods to protect plants from various stresses.**