Metabolomic Profiling of Membrane Lipids and their Compositional Dynamics in Plant Stress Responses

膜脂包括多种分子种类，其组成因膜而异。此外，膜脂的组成变化响应于内部和外部的线索。此外，在膜内，可能存在具有不同脂质成分和特定功能的微结构域。然而，目前尚不清楚这些不同的成分及其动态是如何产生的，以及它们在细胞中的功能是什么。本项目的目的是利用代谢组学方法确定细胞膜脂质的组成，并了解膜脂组成动态在植物对胁迫的响应中的调节和作用。建立了一种基于电喷雾电离串联质谱（ESI-MS/MS）的高灵敏度方法。ESI-MS/MS将用于分析拟南芥在温度和干旱胁迫下的膜脂分子种类，并确定其组成动态。为了了解脂质变化是如何被调节的，本项目将研究参与产生膜脂组成动力学的酶。拟南芥系，取消了磷脂酶D的各种异构体，主要的脂溶酶家族，将有助于分析。此外，研究人员还将分析在硬脂酰acp去饱和酶及其抑制系中存在缺陷的防御突变体ssi2的脂质分子种类，以确定脂质组成与防御反应改变之间的关系。将全脂质分析与产生成分变化的机制的细胞分析相结合的能力将产生关于细胞机制和代谢物如何在细胞对变化环境的反应中以动态方式相互作用的新信息。膜脂是重要的生物成分，是生物膜的结构支柱，也是产生第二信使调节细胞和机体功能的重要资源。膜脂包括多种分子种类，其组成因膜而异。脂质组成随着内外部因素的变化而变化。然而，目前尚不清楚这些不同的成分及其动态是如何产生的，以及它们在细胞中的功能是什么。本项目将建立一种高效的基于电喷雾电离串联质谱的方法，用于测定细胞膜脂质的组成及其变化在植物逆境响应中的作用。对膜脂及其代谢物的广泛分析将产生关于细胞机制和代谢物如何在细胞对变化环境的反应中以动态方式相互作用的前所未有的信息。

Membrane lipids comprise diverse molecular species, and their composition differs from membrane to membrane. In addition, membrane lipid composition changes in response to internal and external cues. Furthermore, within a membrane, there may be microdomains with distinct lipid constituents and particular functions. However, it is not understood how these distinct compositions and their dynamics are generated and what their functions are in the cell. The objectives of this project are to use a metabolomic approach to determine cellular membrane lipid composition and to understand the regulation and role of membrane lipid compositional dynamics in plant responses to stresses. A highly sensitive approach based on electrospray ionization tandem mass spectrometry (ESI-MS/MS) will be established. ESI-MS/MS will be employed to profile membrane lipid molecular species and to determine the compositional dynamics in Arabidopsis plants undergoing temperature and drought stresses. To understand how lipid changes are regulated, this project will investigate enzymes involved in generating the membrane lipid compositional dynamics. Arabidopsis lines, abrogated of various isoforms of phospholipase D, the major lipolytic enzyme family, will be instrumental in the analysis. In addition, lipid molecular species of the defense mutant ssi2 that is defective in stearoyl-ACP desaturase and its suppressor lines will be profiled to determine the relationship between lipid composition and alterations in defense responses. The capability to combine full lipid profiling with cellular analysis of the machinery that generates compositional changes should yield new information on how cellular machinery and metabolites interact in a dynamic manner in the cellular response to changing environments. Membrane lipids are vital biological constituents, providing structural backbones for biological membranes and crucial resources for producing second messengers in regulating cellular and organismal functions. Membrane lipids comprise diverse molecular species, and the composition differs from membrane to membrane. The lipid composition changes in response to internal and external cues. However, it is not understood how these distinct compositions and their dynamics are generated and what their functions are in the cell. This project will establish a highly effective approach based on electrospray ionization tandem mass spectrometry and use it to determine cellular membrane lipid composition and the role of membrane lipid compositional changes in plant responses to stresses. Extensive profiling of membrane lipids and their metabolites will yield unprecedented information on how cellular machinery and metabolites interact in a dynamic manner in the cellular response to changing environments.