title: Stable isotopic labelling-assisted untargeted metabolic profiling reveals novel conjugates of the mycotoxin deoxynivalenol in wheat.
abstract: An untargeted screening strategy for the detection of biotransformation products of xenobiotics using stable isotopic labelling (SIL) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) is reported. The organism of interest is treated with a mixture of labelled and non-labelled precursor and samples are analysed by LC-HRMS. Raw data are processed with the recently developed MetExtract software for the automated extraction of corresponding peak pairs. The SIL-assisted approach is exemplified by the metabolisation of the Fusarium mycotoxin deoxynivalenol (DON) in planta. Flowering ears were inoculated with 100 μg of a 1 + 1 (v/v) mixture of non-labelled and fully labelled DON. Subsequent sample preparation, LC-HRMS measurements and data processing revealed a total of 57 corresponding peak pairs, which originated from ten metabolites. Besides the known DON and DON-3-glucoside, which were confirmed by measurement of authentic standards, eight further DON-biotransformation products were found by the untargeted screening approach. Based on a mass deviation of less than ±5 ppm and MS/MS measurements, one of these products was annotated as DON-glutathione (GSH) conjugate, which is described here for the first time for wheat. Our data further suggest that two DON-GSH-related metabolites, the processing products DON-S-cysteine and DON-S-cysteinyl-glycine and five unknown DON conjugates were formed in planta. Future MS/MS measurements shall reveal the molecular structures of the detected conjugates in more detail.
authors.affiliation: Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Str. 20, 3430 Tulln, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kluger
authors.forename: Christoph
authors.initials: C
authors.lastname: Bueschl
authors.forename: Marc
authors.initials: M
authors.lastname: Lemmens
authors.forename: Franz
authors.initials: F
authors.lastname: Berthiller
authors.forename: Georg
authors.initials: G
authors.lastname: Häubl
authors.forename: Günther
authors.initials: G
authors.lastname: Jaunecker
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
authors.forename: Rudolf
authors.initials: R
authors.lastname: Krska
authors.forename: Rainer
authors.initials: R
authors.lastname: Schuhmacher
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D005670:Fusarium / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods*; D055432:Metabolomics / Q000379:methods*; D015394:Molecular Structure; D053719:Tandem Mass Spectrometry / Q000379:methods; D014255:Trichothecenes / Q000737:chemistry* / Q000378:metabolism*; D014908:Triticum / Q000737:chemistry / Q000382:microbiology*
chemical_list: D014255:Trichothecenes; C007262:deoxynivalenol