Identification and Characterization of Carboxylesterases from Brachypodium distachyon Deacetylating Trichothecene Mycotoxins

Toxins

Clemens Schmeitzl¹  Elisabeth Varga²  Benedikt Warth²  Karl G. Kugler³  Alexandra Malachová²  Herbert Michlmayr¹  Gerlinde Wiesenberger¹  Klaus F. X. Mayer³  Hans-Werner Mewes⁴  Rudolf Krska²  Rainer Schuhmacher²  Franz Berthiller²  Gerhard Adam¹ 

[1] Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria;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;Plant Genome and Systems Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany;Genome oriented Bioinformatics, Technische Universität München, Wissenschaftszentrum Weihenstephan, Am Forum 1, 85354 Freising, Germany;

关键词: Fusarium graminearum;    trichothecene metabolism;    3-acetyl-deoxynivalenol;    15-acetyl-deoxynivalenol;    monocot;    enzymatic cleavage;   

DOI  :  10.3390/toxins8010006

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.