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Meng-Reiterer J.,University of Natural Resources and Life Sciences, Vienna | Meng-Reiterer J.,Institute for Biotechnology in Plant Production | Varga E.,University of Natural Resources and Life Sciences, Vienna | Varga E.,Christian Doppler Laboratory | And 14 more authors.
Analytical and Bioanalytical Chemistry | Year: 2015

An extensive study of the metabolism of the type A trichothecene mycotoxins HT-2 toxin and T-2 toxin in barley using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) is reported. A recently developed untargeted approach based on stable isotopic labelling, LC-Orbitrap-MS analysis with fast polarity switching and data processing by MetExtract software was combined with targeted LC-Q-TOF-MS(/MS) analysis for metabolite structure elucidation and quantification. In total, 9 HT-2 toxin and 13 T-2 toxin metabolites plus tentative isomers were detected, which were successfully annotated by calculation of elemental formulas and further LC-HRMS/MS measurements as well as partly identified with authentic standards. As a result, glucosylated forms of the toxins, malonylglucosides, and acetyl and feruloyl conjugates were elucidated. Additionally, time courses of metabolite formation and mass balances were established. For absolute quantification of those compounds for which standards were available, the method was validated by determining apparent recovery, signal suppression, or enhancement and extraction recovery. Most importantly, T-2 toxin was rapidly metabolised to HT-2 toxin and for both parent toxins HT-2 toxin-3-O-β-glucoside was identified (confirmed by authentic standard) as the main metabolite, which reached its maximum already 1 day after toxin treatment. [Figure not available: see fulltext.] © 2015 The Author(s)

Gong L.,University of Natural Resources and Life Sciences, Vienna | Gong L.,Institute for Biotechnology in Plant Production | Gong L.,North Dakota State University | Paris H.S.,Newe Yaar Research Center | And 7 more authors.
Genetic Resources and Crop Evolution | Year: 2013

Genetic relationships among 88 accessions from nine of the dozen species of Cucurbita (Cucurbitaceae) were assessed from polymorphisms at 74 SSR (simple sequence repeat) loci originating from C. pepo and C. moschata, yielding a total of 315 alleles distributed among 17 linkage groups, with an average of 4. 3 alleles per locus. Genetic distance (GD) values were calculated, a principal coordinate analysis conducted, and a dendrogram constructed. Average within-species genetic distance values ranged from 0. 07 for C. ecuadorensis and C. ficifolia to 0. 46 for C. pepo. Each species was clearly defined, as all mean within-species GD values were lower than the respective mean between-species GD values. C. okeechobeensis had the most central position in the genus Cucurbita, with the lowest average GD to the other species, 0. 61. C. foetidissima, the only xerophytic species examined, was the most distant, with a mean GD of 0. 73 to the other species. C. pepo and C. ficifolia were the most outlying of the mesophytic species. Mean across-species GDs generally corresponded with crossability. However, there were some outstandingly low GD values between particular accessions of Cucurbita pepo, the economically most important species, and disease-resistant wild species, particularly C. okeechobeensis but also C. foetidissima. The results suggest that more intensive search and collection of C. okeechobeensis populations would likely yield genotypes that are more compatible with C. pepo. Moreover, successful application of genetic resources in the genus Cucurbita might be facilitated by using GD values obtained from SSR polymorphisms as a guide in choosing parents for interspecific crossing. © 2012 Springer Science+Business Media Dordrecht.

Nathanail A.V.,Finnish Food Safety Authority | Varga E.,University of Natural Resources and Life Sciences, Vienna | Meng-Reiterer J.,University of Natural Resources and Life Sciences, Vienna | Meng-Reiterer J.,Institute for Biotechnology in Plant Production | And 10 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015

To investigate the metabolic fate of HT-2 toxin (HT2) and T-2 toxin (T2) in wheat (Triticum aestivum L.), an untargeted metabolomics study utilizing stable isotopic labeling and liquid chromatography-high resolution mass spectrometry was performed. In total, 11 HT2 and 12 T2 derived in planta biotransformation products were annotated putatively. In addition to previously reported mono- and diglucosylated forms of HT2, evidence for the formation of HT2-malonyl-glucoside and feruloyl-T2, as well as acetylation and deacetylation products in wheat was obtained for the first time. To monitor the kinetics of metabolite formation, a time course experiment was conducted involving the Fusarium head blight susceptible variety Remus and the resistant cultivar CM-82036. Biotransformation reactions were observed already at the earliest tested time point (6 h after treatment), and formed metabolites showed different kinetic profiles. After ripening, less than 15% of the toxins added to the plants were determined to be unmetabolized. © 2015 American Chemical Society.

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