Okazaki Yozo, Kamide Yukiko, Hirai Masami Yokota, Saito Kazuki
RIKEN Plant Science Center, Tsurumi-ku, Yokohama, 230-0045 Japan.
Metabolomics. 2013 Mar;9(Suppl 1):121-131. doi: 10.1007/s11306-011-0318-z. Epub 2011 May 31.
Plants synthesize a wide range of hydrophobic compounds, generally known as lipids. Here, we report an application of liquid chromatography ion trap time-of-flight mass spectrometry (LC-IT-TOF-MS) for plant lipidomics. Using hydrophilic interaction chromatography (HILIC) for class separation, typical membrane lipids including glycerolipids, steryl glucosides and glucosylceramides, and hydrophobic plant secondary metabolites such as saponins were analyzed simultaneously. By this method, we annotated approximately 100 molecules from . To demonstrate the application of this method to biological study, we analyzed mutant (), which has a complex metabolic phenotype including the accumulation of unusual forms of galactolipids. Lipid profiling by LC-MS revealed that accumulated an unusual form of digalactosyldiacylglycerol, annotated as Gal(β1 → 6)βGalDG. The compositional difference between normal and unusual forms of digalactosyldiacylglycerol was detected by this method. In addition, we analyzed well-known mutants -, - and -, which are also disrupted in lipid metabolic genes. Untargeted lipidome analysis coupled with multivariate analysis clearly discriminated the mutants and their distinctive metabolites. These results indicated that HILIC-MS is an efficient method for plant lipidomics.
植物能合成种类繁多的疏水化合物，一般统称为脂质。在此，我们报告液相色谱离子阱飞行时间质谱（LC-IT-TOF-MS）在植物脂质组学中的应用。采用亲水相互作用色谱（HILIC）进行类别分离，同时分析了包括甘油脂、甾醇糖苷和葡糖神经酰胺在内的典型膜脂，以及如皂苷等疏水植物次生代谢物。通过这种方法，我们从……注释了约100种分子。为证明该方法在生物学研究中的应用，我们分析了突变体……（……），其具有复杂的代谢表型，包括异常形式半乳糖脂的积累。通过LC-MS进行脂质谱分析表明，……积累了一种异常形式的二半乳糖基二酰基甘油，注释为Gal(β1→6)βGalDG。该方法检测到了正常和异常形式二半乳糖基二酰基甘油之间的组成差异。此外，我们分析了著名的……突变体——……、……和……，它们在脂质代谢基因中也存在缺陷。非靶向脂质组分析结合多变量分析能够清晰地区分这些突变体及其独特的代谢物。这些结果表明，HILIC-MS是一种用于植物脂质组学的有效方法。
