Lipid derived signaling involving chloroplasts

涉及叶绿体的脂质衍生信号传导

• 批准号: 2203474
• 负责人: Christoph Benning
• 金额: $ 107.68万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203474&HistoricalAwards=false
• 关键词: Lipid; derived; signaling; involving; chloroplasts

The basic knowledge generated under this project will inspire novel strategies to produce more resilient crop plants that can better cope with a rapidly changing climate. During millions of years of evolution, plants have established the ability to live on land in a fluctuating environment, encountering harsh environmental conditions such as cold, drought, nutrient shortage, pathogen attack, insect outbreaks, or other abiotic or biotic stresses. To combat these challenges, sessile plants resourcefully adjust their internal biological processes, for example by shifting their metabolism from growth to defense. The project explores the interplay of two plant hormones, abscisic acid (ABA) and jasmonic acid (JA), in mediating responses to abiotic and biotic stresses, respectively. The latter originates from membranes in the chloroplast, the place of plant photosynthesis. This project has the potential to discover novel signaling molecules and mechanisms and their modifiers, thereby increasing our understanding of the integration of biotic and abiotic stress responses beyond our current knowledge about the roles of individual signaling molecules. The concepts and techniques of this project offer an exciting experimental platform for studying the integration of biotic and abiotic stress responses that are readily accessible to scientists at all training levels. The project is ideally suited for undergraduate student involvement in a classroom setting as well as through in-lab participation exposing them directly to ongoing real-life research, while teaching them basic scientific principles. A laboratory course, namely a Course-based Undergraduate Research Experience (CURE), has been developed to engage students in the isolation of project-relevant plant mutants and their initial characterization. Individual undergraduate students are involved in the deeper characterization of specific mutants in a research lab environment under the direct mentorship of the participating postdoctoral researchers, who in turn gain mentoring experience preparing them for their next stages in their careers.Chloroplasts are dynamic organelles characterized by an extensive photosynthetic membrane with unique lipids and often respond to biotic and abiotic stresses by lipid remodeling. Lipid turnover in response to external cues often involves the release of acyl groups. These can be further converted into signaling mediators such as JA, divinyl ethers, aldehydes, or other molecules, which can be perceived by plants and trigger plant responses. In many instances, lipases with their lipid hydrolytic activity catalyze the first reaction during lipid remodeling, leading to the initiation of acyl group recycling, when plants are facing insults such as nutrient deprivation, cold, or heat. The project is based on recently characterized plastid lipases, PLIP1-3, from Arabidopsis. Overexpression of the respective coding sequences redirects the metabolism from growth to defense by initiating the biosynthesis and overproduction of oxylipin metabolites such as JA. Loss of PLIP1-3 function triple mutants show sensitivity to ABA. Moreover, the expression of two of the genes, PLIP2 and PLIP3, is responsive to abiotic stressors and ABA, suggesting a possible PLIP2,3-based mechanism in connecting JA and ABA signal transduction pathways in Arabidopsis. Although JA production is most commonly induced by biotic stressors such as wounding due to herbivorous insects, and ABA production is mainly increased by abiotic challenges such as cold, heat, or dehydration, there is increasing evidence of interaction of these signaling pathways as abiotic stressors can stimulate JA biosynthesis and JA can affect the sensitivity of the plant to ABA. The long-term goal of the project is to gain a deeper understanding of how chloroplast membrane lipid-derived signals are produced, transported, perpetuated, perceived, and integrated with different signaling pathways in Arabidopsis to coordinate biotic or abiotic stress responses. To accomplish this goal, the project follows three objectives: 1. Using a genetic suppressor screen in the PLIP3-OX (PLIP3 overexpression) background, the entire information chain from the origin of the lipid-based signal to its perception, transduction, and modification by other signaling pathways is being queried. 2. Suppressor loci are identified by bulk sequencing analysis of segregating suppressor mutant populations. 3. Individual suppressor mutants and affected proteins are characterized for their roles in JA biosynthesis, signaling, and modification by other signaling pathways. Objective 1 and partially objective 2 are conducted by undergraduate students in a classroom setting. Objective 3 involves individual undergraduate students under the mentorship of the participating postdoctoral researchers.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.

该项目产生的基础知识将激发新的策略，以生产更具弹性的农作物，以更好地应对快速变化的气候。在数百万年的进化过程中，植物已经具备了在陆地上不断变化的环境中生存的能力，遇到严酷的环境条件，如寒冷、干旱、营养缺乏、病原体攻击、昆虫爆发或其他非生物或生物胁迫。为了应对这些挑战，固着植物巧妙地调整其内部生物过程，例如将新陈代谢从生长转向防御。该项目探讨了脱落酸（ABA）和茉莉酸（JA）这两种植物激素分别在调节非生物和生物胁迫反应中的相互作用。后者源自叶绿体中的膜，叶绿体是植物光合作用的场所。该项目有可能发现新的信号分子和机制及其修饰剂，从而增加我们对生物和非生物应激反应整合的理解，超出我们目前对单个信号分子作用的了解。该项目的概念和技术为研究生物和非生物应激反应的整合提供了一个令人兴奋的实验平台，所有培训水平的科学家都可以轻松掌握该平台。该项目非常适合本科生参与课堂环境以及通过实验室参与，让他们直接接触正在进行的现实生活研究，同时教授他们基本的科学原理。开发了一个实验室课程，即基于课程的本科生研究体验（CURE），让学生参与项目相关植物突变体的分离及其初步表征。个别本科生在参与的博士后研究人员的直接指导下，在研究实验室环境中参与对特定突变体的更深入表征，而博士后研究人员反过来又获得指导经验，为他们职业生涯的下一阶段做好准备。叶绿体是动态细胞器，其特征是具有广泛的光合膜和独特的脂质，通常通过脂质重塑来响应生物和非生物胁迫。响应外部信号的脂质周转通常涉及酰基的释放。这些可以进一步转化为信号传导介质，如 JA、二乙烯基醚、醛或其他分子，这些分子可以被植物感知并触发植物反应。在许多情况下，当植物面临营养缺乏、寒冷或炎热等侵害时，具有脂质水解活性的脂肪酶会催化脂质重塑过程中的第一个反应，导致酰基回收的启动。该项目基于最近鉴定的来自拟南芥的质体脂肪酶 PLIP1-3。各个编码序列的过度表达通过启动氧脂素代谢物（如 JA）的生物合成和过量生产，将代谢从生长转向防御。 PLIP1-3 功能缺失的三重突变体表现出对 ABA 的敏感性。此外，PLIP2和PLIP3这两个基因的表达对非生物应激源和ABA有反应，这表明拟南芥中可能存在基于PLIP2,3的连接JA和ABA信号转导途径的机制。虽然 JA 的产生最常见是由生物应激源（例如食草昆虫造成的伤害）诱导的，而 ABA 的产生主要是通过非生物挑战（例如冷、热或脱水）来增加的，但越来越多的证据表明这些信号通路之间存在相互作用，因为非生物应激源可以刺激 JA 生物合成，并且 JA 可以影响植物对 ABA 的敏感性。该项目的长期目标是更深入地了解叶绿体膜脂质衍生信号是如何产生、运输、延续、感知以及与拟南芥中不同信号通路整合以协调生物或非生物胁迫反应的。为了实现这一目标，该项目遵循三个目标： 1. 在 PLIP3-OX（PLIP3 过表达）背景下使用基因抑制子筛选，查询从脂质信号的起源到其感知、转导和其他信号通路修饰的整个信息链。 2.通过对分离的抑制突变体群体进行批量测序分析来鉴定抑制基因座。 3. 各个抑制突变体和受影响的蛋白质的特征在于它们在 JA 生物合成、信号传导和其他信号传导途径修饰中的作用。目标 1 和部分目标 2 由本科生在课堂上进行。目标 3 涉及参与博士后研究人员指导下的本科生个人。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。