Trichothecene toxins are confirmed or suspected virulence factors of various plant-pathogenic Fusarium species. Plants can detoxify these to a variable extent by glucosylation, a reaction catalyzed by UDP-glucosyltransferases (UGTs). Due to the unavailability of analytical standards for many trichothecene-glucoconjugates, information on such compounds is limited. Here, the previously identified deoxynivalenol-conjugating UGTs HvUGT13248 (barley), OsUGT79 (rice) and Bradi5g03300 (Brachypodium), were expressed in E. coli, affinity purified, and characterized towards their abilities to glucosylate the most relevant type A and B trichothecenes. HvUGT13248, which prefers nivalenol over deoxynivalenol, is also able to conjugate C-4 acetylated trichothecenes (e.g., T-2 toxin) to some degree while OsUGT79 and Bradi5g03300 are completely inactive with C-4 acetylated derivatives. The type A trichothecenes HT-2 toxin and T-2 triol are the kinetically preferred substrates in the case of HvUGT13248 and Bradi5g03300. We glucosylated several trichothecenes with OsUGT79 (HT-2 toxin, T-2 triol) and HvUGT13248 (T-2 toxin, neosolaniol, 4,15-diacetoxyscirpenol, fusarenon X) in the preparative scale. NMR analysis of the purified glucosides showed that exclusively β-D-glucosides were formed regio-selectively at position C-3-OH of the trichothecenes. These synthesized standards can be used to investigate the occurrence and toxicological properties of these modified mycotoxins.

Biotechnology in Plant Production IFA Tulln BOKU Konrad Lorenz Str 20 3430 Tulln Austria

Christian Doppler Laboratory for Mycotoxin Metabolism and Center for Analytical Chemistry Department of Agrobiotechnology BOKU Konrad Lorenz Str 20 3430 Tulln Austria

Christian Doppler Laboratory for Mycotoxin Metabolism and Center for Analytical Chemistry Department of Agrobiotechnology BOKU Konrad Lorenz Str 20 3430 Tulln Austria Department of Chemistry and Biochemistry Mendel University in Brno Zemědělská 1 613 00 Brno Czech Republic

Department of Applied Genetics and Cell Biology University of Natural Resources and Life Sciences Vienna Konrad Lorenz Str 24 3430 Tulln Austria

Department of Applied Genetics and Cell Biology University of Natural Resources and Life Sciences Vienna Konrad Lorenz Str 24 3430 Tulln Austria Department of Food Chemistry and Toxicology University of Vienna Währinger Str 38 1090 Vienna Austria

Institute of Applied Synthetic Chemistry Vienna University of Technology Getreidemarkt 9 163 1060 Vienna Austria

Institute of Applied Synthetic Chemistry Vienna University of Technology Getreidemarkt 9 163 1060 Vienna Austria CEST Kompetenzzentrum für elektrochemische Oberflächentechnologie GmbH Viktor Kaplan Str 2 2700 Wiener Neustadt Austria

Romerlabs Division Holding GmbH Technopark 1 3430 Tulln Austria

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