To Elucidate N-acylethanolamine Metabolic Pathway And Its Role In Mediating Dehydration Stress Tolerance In Physcomitrella Patens

对自然生长栖息地的干扰会引起植物的应激反应，使它们能够抵抗、容忍或适应这些变化。这种应激反应通常涉及代谢信号网络的激活。本项目的主要目的是研究一种独特的脂质代谢物anandamide在苔藓植物脱水耐受性发育中的代谢和作用。Anandamide通常存在于哺乳动物中，尽管它存在于苔藓中，但尚未在高等植物中报道。在哺乳动物中，这种化合物与神经元信号有关，这增加了它在苔藓中也起到信号作用的可能性。苔藓植物对许多逆境具有天然的耐受性，这项研究有望确定苔藓中存在但在高等植物中不存在的独特脂质是否在苔藓表现出的更强的脱水耐受性中发挥作用。这项研究的发现将揭示脂质介导的生物反应的功能和进化方面的新见解，这些生物学反应可能广泛应用于植物。这些见解可能会导致未来培育耐胁迫作物的策略的发展，有助于在干旱期间和边缘土地上维持粮食生产。该项目还为东田纳西州立大学的研究生和本科生以及一名研究助理提供了急需的研究机会。东田纳西州立大学主要是一所本科院校，吸引了许多来自阿巴拉契亚地区的第一代学生。n -酰基乙醇胺（NAEs）是一类广泛分布于真核生物中的脂肪酸衍生物。在各种类型的NAEs中，已知anandamide与大麻素受体结合，并在哺乳动物中作为多种生理过程的神经调节剂。anandamide是一种20碳多不饱和ω -6脂肪酸乙醇酰胺（NAE 20:4），最近在苔藓植物中发现，但在高等植物中未发现。这一发现开启了一种可能性，即NAEs在早期陆生植物中可能发挥着与动物相似的独特作用，并且在开花植物中所知的范围之外。长期以来，人们一直认为苔藓植物中非常规脂类的存在对它们从水到陆地的成功过渡至关重要，因为脂类可能赋予了它们抵抗高温、耐受渗透和盐胁迫以及脱水的天然能力。因此，假设苔藓可能在进化上保留了独特的NAE代谢物，如anandamide，以及它们介导胁迫耐受性的机制。为了解决这一前提，我们将利用小立壶菌实现三个主要目标：1)生物化学和分子表征NAE代谢途径；2)确定NAE代谢物谱及其对发育的影响；3)阐明NAE在脱落酸介导的脱水耐受中的生理作用。研究将利用其他真核系统的发现，包括调节NAE代谢途径的酶和脂质谱技术。该项目的长期目标是阐明苔藓维持对非生物胁迫的耐受性的机制，这种耐受性可能在维管植物中已经改变或丧失，并揭示植物中脂质介导的生物反应的新功能和进化见解。

Disturbance in the natural growth habitat causes stress responses in plants that enable them to resist, tolerate or adapt to these changes. Such stress responses often involve activation of a network of metabolic signals. The main objective of this project is to study the metabolism and role of a unique lipid metabolite called anandamide in the development of dehydration tolerance in moss plants. Anandamide typically occurs in mammals, and has not been reported in higher plants, despite its occurrence in mosses. In mammals, this compound is involved in neuronal signaling, raising the possibility that it also acts as a signal in mosses. Moss plants are naturally tolerant to many stresses and this study is expected to determine if the unique lipids present in mosses, but absent in higher plants, play a role in the greater dehydration tolerance shown by mosses. The findings from this study will reveal novel functional and evolutionary insights into lipid-mediated biological responses that may be widely applicable in plants. Such insights may lead to development of strategies to generate stress tolerant crop plants in the future, helping to maintain food production during droughts and on marginal lands. The project also offers much needed research opportunities to graduate and undergraduate students and a research associate at East Tennessee State University, which is a primarily undergraduate institution that attracts many regional, first-generation students from the Appalachian region.N-acylethanolamines (NAEs) are a class of fatty acid derivatives that are widely distributed among eukaryotes. Among the various types of NAEs, anandamide is known to bind to cannabinoid receptors and acts as a neuromodulator for a variety of physiological processes in mammals. Recently, anandamide, a 20-carbon, polyunsaturated omega-6 fatty acid ethanolamide (NAE 20:4) was identified in moss plants but not in higher plants. This discovery has opened the possibility that NAEs in early land plants may play a unique role that is akin to that in animals and beyond what is known in flowering plants. The presence of unconventional lipids in bryophytes has long been considered crucial for their successful transition from water to land because lipids may have imparted them with natural ability to resist high temperatures and tolerate osmotic and salt stresses and dehydration. Therefore, it is hypothesized that mosses may have evolutionarily retained unique NAE metabolites, such as anandamide, and mechanisms by which they mediate stress tolerance. To address this premise, three main objectives will be pursued, using Physcomitrella patens: 1) Biochemically and molecularly characterize the NAE metabolic pathway, 2) Determine NAE metabolite profiles and their effects on development, and 3) Elucidate the physiological role of NAEs in abscisic acid-mediated dehydration tolerance. Studies will take advantage of discoveries made in other eukaryotic systems, including the enzymes that regulate NAE metabolic pathway and lipid-profiling techniques. Long-term goals of the project are to elucidate the mechanisms by which mosses maintain tolerance to abiotic stress, which perhaps may have been altered or lost in vascular plants, and reveal novel functional and evolutionary insights into lipid-mediated biological responses in plants.