Lipid derived signaling involving chloroplasts

该项目产生的基本知识将激发新的战略，以生产更有弹性的作物，更好地科普快速变化的气候。在数百万年的进化过程中，植物已经建立了在波动环境中生活在陆地上的能力，遇到恶劣的环境条件，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，无柄植物灵活地调整其内部生物过程，例如将其新陈代谢从生长转移到防御。该项目探讨了两种植物激素，脱落酸（阿坝）和茉莉酸（JA）的相互作用，分别介导对非生物和生物胁迫的反应。后者起源于叶绿体中的膜，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胁迫反应整合的理解，超越我们目前对单个信号分子作用的认识。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随时使用。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中的研究，同时教他们基本的科学原理。一个实验室课程，即基于课程的本科生研究经验（CURE），已经开发，从事学生在项目相关的植物突变体的分离和他们的初步表征。在参与的博士后研究人员的直接指导下，本科生在研究实验室环境中参与特定突变体的更深入表征，从而获得指导经验，为他们的职业生涯的下一阶段做好准备。叶绿体是动态细胞器，其特征是具有独特的脂质的广泛光合膜，并且经常通过脂质重塑来响应生物和非生物胁迫。响应于外部线索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，具有脂质水解活性的脂肪酶在脂质重塑期间催化第一反应，导致当植物面临诸如营养缺乏、冷或热的损伤时酰基再循环的启动。该项目是基于最近表征的质体脂肪酶，PLIP 1 -3，从拟南芥。相应编码序列的过表达通过启动氧化脂素代谢物如JA的生物合成和过量产生将代谢从生长重定向到防御。PLIP 1 -3功能丧失的三重突变体显示出对阿坝的敏感性。此外，两个基因，PLIP 2和PLIP 3的表达，是响应于非生物胁迫和阿坝，这表明一个可能的PLIP 2，3为基础的机制，在连接JA和阿坝信号转导途径在拟南芥。虽然JA的产生最常见的是由生物胁迫，如由于草食性昆虫的伤害，阿坝的产生主要是由非生物的挑战，如冷，热，或脱水增加，有越来越多的证据表明，这些信号转导途径的相互作用，因为非生物胁迫可以刺激JA的生物合成和JA可以影响植物对阿坝的敏感性。该项目的长期目标是更深入地了解叶绿体膜脂源信号是如何产生，运输，延续，感知并与拟南芥中的不同信号通路整合以协调生物或非生物胁迫反应。为实现这一目标，本项目遵循三个目标：1.在PLIP 3-OX（PLIP 3过表达）背景下使用遗传抑制筛选，从基于脂质的信号的起源到其感知，转导和其他信号传导途径的修饰的整个信息链正在被质疑。2.抑制基因座通过分离的抑制基因突变群体的批量测序分析来鉴定。3.个体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、信号传导和通过其他信号传导途径修饰中的作用。目标1和部分目标2由本科生在课堂环境中进行。目标3涉及在参与博士后研究人员指导下的个别本科生。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。

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.