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Mass Spectrometric Imaging of Plant Metabolites

We are developing mass spectrometric imaging techniques to map metabolite distributions within plant tissues, and eventually among individual plant cells. Such details will ultimately lead to a predictive understanding of the mechanisms that multicellular organisms use to regulate metabolic processes. By studying the diversity of the cuticular waxes, we hope to gain detailed insight into their biosynthesis as a function of genetics, tissue type, development, and environment. A laser beam will be used to interrogate sequentially micrometer areas of a plant by vaporizing the surface contents of the tissue into a mass spectrometer. Rastering of the laser beam over the tissue will produce a laterally resolved image of the various substances within different structures of the plant. Repeated vaporization at the same focused point of a plant structure will produce a depth profile of the components. We plan to generate ions directly from the plant tissue by designing novel additives as pseudo-matrixes.

This research is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences through the Ames Laboratory.  The Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358

Project Leader: Basil Nikolau

Principal Investigators: Robert Houk, Jiyoung Lee, Young-jin Lee

  • Scientists have advanced methods to make maps of the locations of molecules within plant materials. Resolution of 10 to 50 microns, less than a quarter the size of a human hair, is routinely possible. The trick with plant materials is to extract the molecules delicately from thin slices with a fine laser moving stepwise across the sample.Many molecules are analyzed at once using a very sensitive mass spectrometer in this technique known as matrix-assisted laser deposition/ionization-mass spectrometry imaging (MALDI-MS).