Identification and characterization of carboxylesterases from brachypodium distachyon deacetylating trichothecene mycotoxins

Clemens Schmeitzl, Elisabeth Varga, Benedikt Warth, Karl G. Kugler, Alexandra Malachová, Herbert Michlmayr, Gerlinde Wiesenberger, Klaus F.X. Mayer, Hans Werner Mewes, Rudolf Krska, Rainer Schuhmacher, Franz Berthiller, Gerhard Adam

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

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.

Original languageEnglish
Article number6
JournalToxins
Volume8
Issue number1
DOIs
StatePublished - 25 Dec 2015

Keywords

  • 15-acetyl-deoxynivalenol
  • 3-acetyl-deoxynivalenol
  • Enzymatic cleavage
  • Monocot
  • Trichothecene metabolism
  • Usarium graminearum

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