title: Functional characterization of two clusters of Brachypodium distachyon UDP-glycosyltransferases encoding putative deoxynivalenol detoxification genes.
abstract: Plant small-molecule UDP-glycosyltransferases (UGT) glycosylate a vast number of endogenous substances but also act in detoxification of metabolites produced by plant-pathogenic microorganisms. The ability to inactivate the Fusarium graminearum mycotoxin deoxynivalenol (DON) into DON-3-O-glucoside is crucial for resistance of cereals. We analyzed the UGT gene family of the monocot model species Brachypodium distachyon and functionally characterized two gene clusters containing putative orthologs of previously identified DON-detoxification genes from Arabidopsis thaliana and barley. Analysis of transcription showed that UGT encoded in both clusters are highly inducible by DON and expressed at much higher levels upon infection with a wild-type DON-producing F. graminearum strain compared with infection with a mutant deficient in DON production. Expression of these genes in a toxin-sensitive strain of Saccharomyces cerevisiae revealed that only two B. distachyon UGT encoded by members of a cluster of six genes homologous to the DON-inactivating barley HvUGT13248 were able to convert DON into DON-3-O-glucoside. Also, a single copy gene from Sorghum bicolor orthologous to this cluster and one of three putative orthologs of rice exhibit this ability. Seemingly, the UGT genes undergo rapid evolution and changes in copy number, making it difficult to identify orthologs with conserved substrate specificity.
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, A-3430 Tulln, Austria. wofgang.schweiger@boku.ac.at
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schweiger
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Pasquet
authors.forename: Thomas
authors.initials: T
authors.lastname: Nussbaumer
authors.forename: Maria Paula Kovalsky
authors.initials: MP
authors.lastname: Paris
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Wiesenberger
authors.forename: Catherine
authors.initials: C
authors.lastname: Macadré
authors.forename: Christian
authors.initials: C
authors.lastname: Ametz
authors.forename: Franz
authors.initials: F
authors.lastname: Berthiller
authors.forename: Marc
authors.initials: M
authors.lastname: Lemmens
authors.forename: Patrick
authors.initials: P
authors.lastname: Saindrenan
authors.forename: Hans-Werner
authors.initials: HW
authors.lastname: Mewes
authors.forename: Klaus F X
authors.initials: KF
authors.lastname: Mayer
authors.forename: Marie
authors.initials: M
authors.lastname: Dufresne
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
mesh_terms: D000595:Amino Acid Sequence; D058431:Brachypodium / Q000201:enzymology* / Q000235:genetics; D005670:Fusarium / Q000737:chemistry / Q000472:pathogenicity*; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D023061:Gene Order; D005960:Glucosides / Q000378:metabolism; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009183:Mycotoxins / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000201:enzymology / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D045868:Sorghum / Q000201:enzymology / Q000235:genetics; D013045:Species Specificity; D026801:Synteny; D014255:Trichothecenes / Q000378:metabolism*
chemical_list: D005960:Glucosides; D009183:Mycotoxins; D010940:Plant Proteins; D014255:Trichothecenes; C542050:deoxynivalenol-3-glucoside; D016695:Glycosyltransferases; C007262:deoxynivalenol