Fast phenotyping of LFS-silenced (tearless) onions by desorption electrospray ionization mass spectrometry (DESI-MS).

Fast MS techniques have been applied to the analysis of sulfur volatiles in Allium species and varieties to distinguish phenotypes. Headspace sampling by proton transfer reaction (PTR) MS and surface sampling by desorption electrospray ionization (DESI) MS were used to distinguish lachrymatory factor synthase (LFS)-silenced (tearless; LFS-) onions from normal, LFS-active (tear-inducing; LFS+), onions. PTR-MS showed lower concentrations of the lachrymatory factor (LF, 3) and dipropyl disulfide 12 from tearless onions. DESI-MS of the tearless onions confirmed the decreased LF 3 and revealed much higher concentrations of the sulfenic acid condensates. Using DESI-MS with MS(2) could distinguish zwiebelane ions from thiosulfinate ions. DESI-MS gave reliable fast phenotyping of LFS+ versus LFS- onions by simply scratching leaves and recording the extractable ions for <0.5 min. DESI-MS leaf compound profiles also allowed the rapid distinction of a variety of Allium cultivars to aid plant breeding selections.

[1]  R. Musah,et al.  Applications of direct analysis in real time-mass spectrometry (DART-MS) in Allium chemistry. (Z)-butanethial S-oxide and 1-butenyl thiosulfinates and their S-(E)-1-butenylcysteine S-oxide precursor from Allium siculum. , 2010, Journal of agricultural and food chemistry.

[2]  Masahiro Kato,et al.  Structure and bioactivity of thiosulfinates resulting from suppression of lachrymatory factor synthase in onion. , 2011, Journal of agricultural and food chemistry.

[3]  Patrik Španěl,et al.  Selected ion flow tube – mass spectrometry: detection and real-time monitoring of flavours released by food products , 1999 .

[4]  H. Hirota,et al.  Identification of Amino Acid Residues Essential for Onion Lachrymatory Factor Synthase Activity , 2012, Bioscience, biotechnology, and biochemistry.

[5]  P. Newton,et al.  Reactive desorption electrospray ionization linear ion trap mass spectrometry of latest-generation counterfeit antimalarials via noncovalent complex formation. , 2007, Analytical chemistry.

[6]  R. Cody,et al.  Crushing Garlic and Slicing Onions: Detection of Sulfenic Acids and Other Reactive Organosulfur Intermediates from Garlic and Other Alliums using Direct Analysis in Real-Time Mass Spectrometry (DART-MS) , 2011 .

[7]  R. Musah,et al.  First insights into the mode of action of a "lachrymatory factor synthase"--implications for the mechanism of lachrymator formation in Petiveria alliacea, Allium cepa and Nectaroscordum species. , 2011, Phytochemistry.

[8]  Masahiro Kato,et al.  Silencing Onion Lachrymatory Factor Synthase Causes a Significant Change in the Sulfur Secondary Metabolite Profile1[W][OA] , 2008, Plant Physiology.

[9]  R. Cooks,et al.  Mass Spectrometry Sampling Under Ambient Conditions with Desorption Electrospray Ionization , 2004, Science.

[10]  T. Nagata,et al.  Plant biochemistry: An onion enzyme that makes the eyes water , 2002, Nature.

[11]  N. Tsuge,et al.  Proton Transfer in a Reaction Catalyzed by Onion Lachrymatory Factor Synthase , 2012, Bioscience, biotechnology, and biochemistry.

[12]  R. Musah,et al.  Discovery and Characterization of a Novel Lachrymatory Factor Synthase in Petiveria alliacea and Its Influence on Alliinase-Mediated Formation of Biologically Active Organosulfur Compounds1[W][OA] , 2009, Plant Physiology.

[13]  P. Monks,et al.  Proton-transfer reaction mass spectrometry. , 2009, Chemical reviews.

[14]  Yinlong Guo,et al.  Observation of allicin-cysteine complex by reactive desorption electrospray ionization mass spectrometry for garlic. , 2008, Rapid communications in mass spectrometry : RCM.

[15]  R. Cooks,et al.  Internal energy distributions in desorption electrospray ionization (DESI) , 2008, Journal of the American Society for Mass Spectrometry.

[16]  Willie O. Chance,et al.  Rapid Extraction Method of Quantitating the Lachrymatory Factor of Onion Using Gas Chromatography , 1996 .

[17]  T. Bayer,et al.  Allium Chemistry: Synthesis and Sigmatropic Rearrangements of Alk(en)yl 1-Propenyl Disulfide S-Oxides from Cut Onion and Garlic1 , 1996 .

[18]  Anders Feilberg,et al.  Investigation of Volatiles Emitted from Freshly Cut Onions (Allium cepa L.) by Real Time Proton-Transfer Reaction-Mass Spectrometry (PTR-MS) , 2012, Sensors.

[19]  R. Cody,et al.  Applications of direct analysis in real time mass spectrometry (DART-MS) in Allium chemistry. 2-propenesulfenic and 2-propenesulfinic acids, diallyl trisulfane S-oxide, and other reactive sulfur compounds from crushed garlic and other Alliums. , 2010, Journal of agricultural and food chemistry.