Collaborative Research: Lipidomic Profiling, Dynamics, and Functions of Head-group Acylation of Membrane Lipids in Plant Stress Responses

在植物的细胞中，脂质形成膜，将细胞与其环境分开，并将细胞内的隔室彼此分开。这些脂质也有重要的代谢和信号功能，直到现在才被建立起来。随着植物的发育和暴露于环境信号中，膜脂被广泛地化学修饰。脂质分析的最新进展表明，在膜脂上添加脂肪酸，称为极性脂质头基酰化，是一个主要的修饰过程，但对这一过程及其生理意义知之甚少。本项目将探讨脂质头基酰化在提高植物对环境胁迫的适应性方面的作用。为了确定植物在逆境中头群酰化的作用，将鉴定编码头群酰化脂质代谢的酶的基因。通过检测缺失这些基因和酶的植物，并与含有这些基因和酶的植物进行比较，将确定膜脂头基酰化在植物胁迫反应中的作用。这些活动将确定有可能提高植物抗逆性和提高农业生产力和质量的代谢步骤。相关数据将被整合到植物功能基因组知识库中。此外，这项工作将为博士后受训者提供生物统计学、化学和生物学方面的跨学科培训，并将通过与历史上黑人朗斯顿大学的一名教师导师和本科生合作，扩大代表性不足群体对研究的参与。本项目旨在提高目前对膜脂修饰在生产和维持复杂细胞膜以及影响机体性能中的作用的理解。在全甘油脂质体的背景下，新的基于质谱的方法将用于识别和表征脂质头基酰化在生物应激（丁香假单胞菌感染）和非生物应激（磷酸盐缺乏）下的变化。为了确定负责头群酰化的基因产物，将获得候选基因敲除突变体的脂质谱，并将其与野生型植物的脂质谱进行比较。基因敲除突变体在逆境下的功能分析数据将与脂质水平相关，从而提供有关头群酰化在植物功能中的作用的额外信息。还将测试在植物上施用酰化头基或头基酰化脂的效果。脂质分析和功能数据将集成到一个新的代谢数据库，以扩大代谢网络的知识。

In the cells of a plant, lipids form membranes that separate the cell from its environment and compartments within the cell from one another. These lipids also have crucial metabolic and signaling functions that are only now being established. As plants develop and are exposed to environmental signals, membrane lipids are extensively chemically modified. Recent advances in lipid analysis have revealed that addition of a fatty acid to a membrane lipid, called polar lipid head-group acylation, is a major modification process, but relatively little is known about this process or its physiological significance. This project will address the hypothesis that head-group acylation of lipids functions to improve plant adaptation to environmental stress. To identify the role of head-group acylation when plants are under stress, genes encoding enzymes responsible for head-group-acylated lipid metabolism will be identified. By examining plants that are missing these genes and enzymes, in comparison to plants that contain them, the functions of membrane lipid head-group acylation in plant stress responses will be determined. These activities will identify metabolic steps with potential to enhance stress tolerance in plants and improve agricultural productivity and quality. Relevant data will be integrated into a plant functional genomic knowledge base. Further, the work will provide interdisciplinary training in biostatistics, chemistry, and biology to postdoctoral trainees, and it will broaden the participation of underrepresented groups in research through collaboration with a faculty mentor and undergraduate student at historically black Langston University.This project aims to improve current understanding of the role of membrane lipid modification in producing and maintaining complex cell membranes, and influencing organismal performance. In the context of whole glycerolipidomes, new mass spectrometry-based approaches will be used to identify and characterize changes in lipid head-group acylation in response to a biotic stress, Pseudomonas syringae infection, and an abiotic stress, phosphate deficiency. To identify the gene product(s) responsible for head-group acylation, the lipid profiles of knockout mutants of candidate genes will be obtained and compared to the lipid profiles of wild-type plants. Data from functional analysis of the knockout mutants under stress will be correlated with lipid levels, providing additional information about the roles of head-group acylation in plant function. The effects of application of acylated head groups or head-group acylated lipids to plants also will be tested. Lipid profiling and functional data will be integrated into a novel metabolic database to expand knowledge of metabolic networks.