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

Abstract

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 Hex 11 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.

MALDI Mass Spectrometry Imaging for the Simultaneous Location of Resveratrol, Pterostilbene and Viniferins on Grapevine Leaves

“…For mass spectrometry imaging purpose, MALDI has already been used to map different metabolites on plant organs [28] such as lipids on leaf surface [29], flavonoids or glycoalkaloid in roots and root nodules [30,31], sugars within seed or stem sections [32,33]. Different matrices are described in the literature for MALDI MS analysis of vegetable material such as 1,5 diamino naphthalene (DAN) or 9-amino acridine (9-AA) in negative ion mode, and tri-hydroxy acetophenone (THAP), α-cyano-4-hydroxy cinamic acid (CHCA) or 2,5 dihydroxy-benzoic acid (DHB) in positive ion mode.…”

“…The relative intensities of fragments are indicated in parenthesis. (20) ; 411 (10) ; 369 (12) (38) ; 347 (40) ; 333 (50) ; 317 (14) ; 307 (20) ; 267 (12) ; 251 (13) (38) ; 159 (32) ; 157 (29) ; 143 (11) The extraction sample of grapevine leaf irradiated by UV was also investigated by MALDI-TOFMS with DHB as the matrix (and 0.1% of TFA). The average mass spectrum obtained from 50 mass spectra is displayed in the Figure 2.…”

Nonuniform distribution of glucosinolates in Arabidopsis thaliana leaves has important consequences for plant defense

“…Diverse analytes have been characterized by MALDI-TOF imaging including drugs, peptides, and proteins in animal tissues (16), and herbicides (17) and peptides (18) in plants. However, despite several very recent reports on MALDI imaging of sugars in plants (19,20), the distribution of secondary natural products in intact plant tissue has not been determined by using mass spectrometric imaging. Moreover, in most cases the distribution of compounds determined by mass spectrometric imaging has not been validated by using independent methods.…”

Ethylenediaminetetraacetic acid (EDTA) as an auxiliary tool in the electrospray ionization mass spectrometry analysis of native and derivatized β-cyclodextrins, maltoses, and fructans contaminated with Ca and/or Mg

“…Model compounds such as maltoses (maltose to maltoheptaose), ␤-cyclodextrins (␤-cyclodextrin, methyl-␤-cyclodextrin, heptakis(2,6-di-O-methyl)-␤-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-␤-cyclodextrin, and 2-hydroxypropyl-␤-cyclodextrin) and fructans (sucrose, 1-ketose, nystose, and 1F-fructofuranosylnystose) were used. (J Am Soc Mass Spectrom 2010, 21, 1526 -1529) © 2010 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry I mportant advances in the direct analysis of soluble carbohydrates present in plant cells and tissues, such as probe electrospray (PESI) mass spectrometry (MS) [1], pressure probe and ultraviolet matrix assisted laser desorption/ionization (UV-MALDI) MS [2], and direct UV-MALDI-MS of tissues [3][4][5][6], have been recently reported. Studies of carbohydrate MS analysis generally deals with complex mixtures isolated from dry powdered plant tissues [7][8][9][10].…”

“…Carbohydrates soluble in cell sap are in an aqueous solution containing cations such as K ϩ (50 -100 mM), Na ϩ (5.0 -5.5 mM), as well as Mg 2ϩ and Ca 2ϩ (Ͻ2.5 mM) [11]. Thus, soluble carbohydrates are detected in MS positive ion mode mainly as potassiated species ([M ϩ K] ϩ ) [1][2][3][4][5][6][7][8][9] and in negative mode as deprotonated species ([M Ϫ H] Ϫ ) by using either sucked cell sap [2] or direct cell/tissue MS analysis [1,[3][4][5][6].…”