title: Identification and Characterization of Carboxylesterases from Brachypodium distachyon Deacetylating Trichothecene Mycotoxins.
abstract: Increasing frequencies of 3-acetyl-deoxynivalenol (3-ADON)-producing strains of Fusarium graminearum (3-ADON chemotype) have been reported in North America and Asia. 3-ADON is nearly nontoxic at the level of the ribosomal target and has to be deacetylated to cause inhibition of protein biosynthesis. Plant cells can efficiently remove the acetyl groups of 3-ADON, but the underlying genes are yet unknown. We therefore performed a study of the family of candidate carboxylesterases (CXE) genes of the monocot model plant Brachypodium distachyon. We report the identification and characterization of the first plant enzymes responsible for deacetylation of trichothecene toxins. The product of the BdCXE29 gene efficiently deacetylates T-2 toxin to HT-2 toxin, NX-2 to NX-3, both 3-ADON and 15-acetyl-deoxynivalenol (15-ADON) into deoxynivalenol and, to a lesser degree, also fusarenon X into nivalenol. The BdCXE52 esterase showed lower activity than BdCXE29 when expressed in yeast and accepts 3-ADON, NX-2, 15-ADON and, to a limited extent, fusarenon X as substrates. Expression of these Brachypodium genes in yeast increases the toxicity of 3-ADON, suggesting that highly similar genes existing in crop plants may act as susceptibility factors in Fusarium head blight disease.
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria. Clemens.schmeitzl@boku.ac.at.
authors.forename: Clemens
authors.initials: C
authors.lastname: Schmeitzl
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. elisabeth.varga@boku.ac.at.|Christian Doppler Laboratory for Mycotoxin Metabolism, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. elisabeth.varga@boku.ac.at.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Varga
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. alexandra.malachova@boku.ac.at.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Warth
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany. karl.kugler@helmholtz-muenchen.de.
authors.forename: Karl G
authors.initials: KG
authors.lastname: Kugler
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. rudolf.krska@boku.ac.at.|Christian Doppler Laboratory for Mycotoxin Metabolism, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. rudolf.krska@boku.ac.at.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Malachová
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria. herbert.michlmayr@boku.ac.at.
authors.forename: Herbert
authors.initials: H
authors.lastname: Michlmayr
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria. gerlinde.wiesenberger@boku.ac.at.
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Wiesenberger
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany. kmayer@helmholtz-muenchen.de.
authors.forename: Klaus F X
authors.initials: KF
authors.lastname: Mayer
authors.affiliation: Genome oriented Bioinformatics, Technische Universität München, Wissenschaftszentrum Weihenstephan, Am Forum 1, 85354 Freising, Germany. w.mewes@wzw.tum.de.
authors.forename: Hans-Werner
authors.initials: HW
authors.lastname: Mewes
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. rudolf.krska@boku.ac.at.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Krska
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. rainer.schuhmacher@boku.ac.at.
authors.forename: Rainer
authors.initials: R
authors.lastname: Schuhmacher
authors.affiliation: Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. franz.berthiller@boku.ac.at.|Christian Doppler Laboratory for Mycotoxin Metabolism, Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. franz.berthiller@boku.ac.at.
authors.forename: Franz
authors.initials: F
authors.lastname: Berthiller
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria. gerhard.adam@boku.ac.at.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
mesh_terms: D000107:Acetylation; D058431:Brachypodium / Q000201:enzymology / Q000235:genetics*; D002265:Carboxylic Ester Hydrolases / Q000235:genetics* / Q000378:metabolism*; D017343:Genes, Plant; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014255:Trichothecenes / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity
chemical_list: D010940:Plant Proteins; D014255:Trichothecenes; D002265:Carboxylic Ester Hydrolases
keywords: 15-acetyl-deoxynivalenol; 3-acetyl-deoxynivalenol; Fusarium graminearum; enzymatic cleavage; monocot; trichothecene metabolism