Plasmodesmata and chloroplasts in integrative defense signaling

胞间连丝和叶绿体在综合防御信号传导中的作用

• 批准号: 2054685
• 负责人: Jung-Youn Lee
• 金额: $ 91.18万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2054685&HistoricalAwards=false
• 关键词: Plasmodesmata; chloroplasts; integrative; defense; signaling

One of the most effective ways to stop spreading a contagious disease is self-isolation. However, when self-isolation does not happen at the right timing, the spread of disease could go unruly. This is also true at the cellular level whether it concerns an animal or plant system. Upon a successful recognition of invading pathogen, host cells deploy defense programs to fight off pathogens. This often involves a phenomenon called programmed cell death, which is an effective immune response. However, if a cell or group of cells undergo cell death without appropriately communicating for neighboring cells to survive, it could result in an unwanted death of the whole organism. Therefore, understanding how cells regulate the relay of cell death or health signal is not only critical to advance our knowledge but also to help engineer new ways to boost host immunity. In plants, various immune signals are produced in chloroplasts, and it is known that both chloroplasts and the intercellular bridges called plasmodesmata are vital for plant defense. Through multi-disciplinary research proposed in this project, the research team aims to investigate how infected cells in plants might deliver chloroplastic immune signals to plasmodesmata and communicate with their surrounding cells to differentially relay death and health signals at the right time and right place. These investigations will be performed using state-of-the-art live-cell imaging techniques and genetically encoded fluorescent sensors introduced into mutant plants that are altered in chloroplasts mobility or plasmodesmal function.Upon pathogen infection, plants can elicit the hypersensitive response (HR), triggering programmed cell death (PCD) of the infected cells while preserving the health of the surrounding cells. HR-PCD is a highly effective form of plant immunity that can potentially lead to new solutions for boosting agricultural productivity without relying heavily on biocides. However, it remains unknown how HR-PCD is contained to just those cells within and near the infection sites. Here, the research team proposes to explore the signal relay between the HR-PCD cells and the healthy cells bordering them. Specifically, they will focus on hydrogen peroxide (H2O2), which is a key type of reactive oxygen species (ROS) required for HR-PCD. The team will track how the H2O2 burst from intracellular chloroplasts is delivered to restrict molecular movement through the plasmodesmata connecting cells within the HR-PCD site and healthy cells surrounding it. Major research aims include: 1) Establishing the timeline between H2O2 burst and PD status; 2) Investigating the potential of a localized H2O2 burst at PD; 3) Exploring the modes of PD regulation within and outside HR-PCD cells. The research team envisions delivering, for the first time, a high-resolution, real-time plasmodesmal permeability map displaying how chloroplast-plasmodesmata interactions may occur at the intra- and intercellular levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

阻止传染病传播的最有效方法之一是自我隔离。然而，当自我隔离没有在正确的时间发生时，疾病的传播可能会失控。在细胞水平上也是如此，无论它涉及动物还是植物系统。一旦成功识别入侵的病原体，宿主细胞就会部署防御程序来对抗病原体。这通常涉及一种称为程序性细胞死亡的现象，这是一种有效的免疫反应。然而，如果一个细胞或一组细胞经历细胞死亡，而没有适当地与相邻细胞进行通信以存活，则可能导致整个生物体的不必要的死亡。因此，了解细胞如何调节细胞死亡或健康信号的传递不仅对推进我们的知识至关重要，而且有助于设计新的方法来增强宿主免疫力。在植物中，叶绿体中产生各种免疫信号，并且已知叶绿体和称为胞间连丝的细胞间桥梁对于植物防御至关重要。通过本项目提出的多学科研究，研究团队旨在研究植物中受感染的细胞如何将叶绿体免疫信号传递到胞间连丝，并与周围细胞进行交流，以在正确的时间和正确的地点有区别地传递死亡和健康信号。这些研究将使用最先进的活细胞成像技术和基因编码的荧光传感器来进行，这些荧光传感器被引入到叶绿体移动性或胞间连丝功能改变的突变体植物中。当病原体感染时，植物可以引发过敏反应（HR），触发受感染细胞的程序性细胞死亡（PCD），同时保护周围细胞的健康。 HR-PCD是一种非常有效的植物免疫形式，可以潜在地为提高农业生产力提供新的解决方案，而无需严重依赖生物杀灭剂。 然而，目前尚不清楚HR-PCD如何仅限于感染部位内和附近的那些细胞。 在这里，研究小组建议探索HR-PCD细胞和与它们相邻的健康细胞之间的信号传递。 具体来说，他们将专注于过氧化氢（H2 O2），这是HR-PCD所需的一种关键类型的活性氧（ROS）。研究小组将追踪细胞内叶绿体释放的H2 O2如何通过连接HR-PCD部位细胞和周围健康细胞的胞间连丝限制分子运动，主要研究目的包括：1）建立H2 O2爆发和PD状态之间的时间轴; 2）研究PD时局部H2 O2爆发的可能性;（3）探索HR-PCD细胞内外PD调控的模式。该研究小组设想首次提供一个高分辨率、实时的胞间连丝渗透图，显示叶绿体-胞间连丝相互作用如何在细胞内和细胞间水平发生。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。