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Localization of water-soluble carbohydrates in wheat stems using imaging matrix-assisted laser desorption ionization mass spectrometry

Authors


Author for correspondence: J. Thomas-Oates Tel: +44 (0) 1904 434459 Fax: +44 (0) 1904 432516 Email: jeto1@york.ac.uk

Summary

  • • The pool of endogenous water-soluble oligosaccharides found in the stems of wheat (Triticum aestivum) is being investigated as a potential indicator of grain yield. Techniques such as liquid chromatography with mass spectrometry (LC-MS) can profile these analytes but provide no spatial information regarding their distribution in the wheat stem. The imaging matrix-assisted laser desorption ionization (MALDI) mass spectrometry technique has not been utilized for the analysis of oligosaccharides in plant systems previously.
  • • Imaging MALDI mass spectrometry was used to analyse cross and longitudinal sections from the stems of Triticum aestivum.
  • • A range of oligosaccharides up to Hex11 were observed. Water-soluble oligosaccharides were ionized as potassiated molecules, and found to be located in the stem pith that is retained predominantly around the inner stem wall.
  • • Imaging MALDI analyses provided spatial information on endogenous oligosaccharides present in wheat stems. The technique was found to offer comparable sensitivities for oligosaccharide detection to those of our established LC-MS method, and has potential for broad application in studying the in situ localization of other compound types in plant material.

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