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Session 4 – Biotic and Abiotic Stresses S4.3- Use of the pathosystem Brachypodium distachyon / Fusarium graminearum to investigate the detoxification mechanisms of mycotoxins by plants. Jean-Claude Pasquet, Catherine Macadré, Xavier Deguercy, Patrick Saindrenan and Marie Dufresne Institut de Biologie des Plantes, Université Paris-Sud 11, 91405 Orsay, France marie.dufresne@u-psud.fr Abstract Fusarium head blight (FHB), caused primarily by Fusarium graminearum, is one of the most damaging diseases on small-grain cereals, including wheat (Goswami and Kistler, 2004). During its development in the host plant, this pathogen produces trichothecene mycotoxins (including deoxynivalenol or DON) that inhibit eukaryotic protein translation, are harmful to humans, animals (Rocha et al. 2005) and also phytotoxic (Desmond et al. 2008). No gene-for-gene resistance has been reported towards F. graminearum but quantitative trait loci (QTL) were identified in bread wheat. Genetic, metabolic or transcriptional analyses have correlated some of these QTLs with functions involved in DON detoxification, including UDP-glycosyltransferases (UGTs). Our team recently developed a new pathosystem, the intereaction between the small cereal species Brachypodium distachyon and F. graminearum, and uses it to study the mechanisms of DON detoxification. Based on phylogenetic relationships with UGTs identified in Arabidopsis (Poppenberger et al. 2003) or barley (Gardiner et al. 2010), we have identified four candidate UGTs from B. distachyon potentially involved in this process and first investigated how DON or infection by F. graminearum can regulate the expression of the corresponding genes, using quantitative RT-PCR analyses. We have shown that the expression of all four candidate genes is strongly induced between 72 and 96 hours after inoculation by F. graminearum and as soon as 3 hours after application of DON. By monitoring the expression of the Tri5 gene (gene encoding the first enzyme of the trichothecene biosynthetic pathway, Foroud and Eudes, 2009), we have further demonstrated that DON is likely produced at stages where the candidate genes are induced. Functional analyses of these genes are underway in B. distachyon to decipher more precisely their involvement in DON detoxification and in resistance towards FHB. References Foroud NA, Eudes F (2009) Trichothecenes in cereals grains. International Journal of Molecular Sciences 10: 147-173 Gardiner SA, Boddu J, Berthiller F, et al. (2010) Transcriptome analysis of the barleydeoxynivalenol interaction: evidence for a role of glutathione in deoxynivalenol detoxification. Molecular Plant-Microbe Interactions 23: 962-976 Goswami RS, Kistler HC (2004) Heading for disaster: Fusarium graminearum on cereal crops. Molecular Plant Pathology 5: 515-525 Poppenberger B, Berthiller F, Lucyshyn D, et al. (2003) Detoxification of the Fusarium mycotoxin deoxynivalenol by a UDP-glucosyltransferase from Arabidopsis thaliana. The Journal of Biological Chemistry 48: 47905-47914 Rocha O, Ansari K, Dooham FM (2005) Effects of trichothecens mycotoxins on eukaryotic cells: A review. Food additives and contaminants 22: 369-378 Keywords Fusarium graminearum, deoxynivalenol, detoxification, UDP-glycosyltransferases 33
Session 4 – Biotic and Abiotic Stresses S4.4- Functional characterization of Brachypodium UDP-glucosyltransferases 1Wolfgang Schweiger, 1Maria Paula Kovalski, 1Juan Antonio Torres Acosta, 2Marc Lemmens, 3Hikmet Budak, 3Franz Berthiller, 4Thomas Nussbaumer, 4Klaus Mayer, 1Gerhard Adam 1 Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Konrad Lorenz Str. 25, A-3430 Tulln, Austria 2 Department IFA Tulln (BOKU), Konrad Lorenz Str. 20, A-3430 Tulln, Austria 3 Sabanci University Faculty of Engineering and Natural Sciences, Orhanli, Tuzla-Istanbul, Turkey 4 Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München, Neuherberg, Germany gerhard.adam@boku.ac.at Abstract Fusarium graminearum is an important fungal pathogen of small grain cereals and maize. It produces the protein biosynthesis inhibitor and mycotoxin deoxynivalenol, which is a virulence factor supporting fungal spread in infected ears. Resistance to Fusarium is at least partly determined by the ability to convert DON into the non-toxic conjugate DON-3-O-glucoside (Poppenberger et al. 2003). Also Brachypodium can be infected with Fusarium, and different accessions can form the detoxification product to a variable extent. The gene family of Bd UDP-glucosyltransferases (UGTs) consists of 177 predicted genes. We characterized the cluster of 6 Bd genes which have the highest sequence similarity with a barley gene HvUGT13248 conferring toxin resistance in yeast (Schweiger et al. 2010). Only two out of the six Bd homologs confered DON resistance. We conclude that the UGTs, which frequently occur in clusters containing a variable number of genes compared to rice and sorghum, seem to evolve very rapidly. It is therefore nontrivial to identify the true orthologs in crop plants. Validation of the presumed function of candidate genes by heterologus expression and functional testing in yeast is warranted. References References Poppenberger B, Berthiller F, Lucyshyn D, Sieberer T, Schuhmacher R, Krska R, Kuchler K, Glössl J, Luschnig C, Adam G (2003) Detoxification of the Fusarium mycotoxin deoxynivalenol by a UDP-glucosyltransferase from Arabidopsis thaliana. J. Biol. Chem. 278: 47905-47914. Schweiger W, Boddu J, Shin S, Poppenberger B, Berthiller F, Lemmens M, Muehlbauer GJ, Adam G (2010) Validation of a candidate deoxynivalenol-inactivating UDPglucosyltransferase from barley by heterologous expression in yeast. Mol. Plant Microbe Interact. 23: 962-76. Keywords Fusarium, mycotoxin, detoxification, resistance 34
Page 2 and 3: Acknowledgements: Institut National
Page 4 and 5: Contents Programme 4 Oral presentat
Page 6 and 7: Wednesday 19 th October, 2011 11:00
Page 8 and 9: Friday 21 st October, 2011 Biotic a
Page 10 and 11: ORAL COMMUNICATIONS 9
Page 12 and 13: Session 1 - Evolution and Natural V
Page 18 and 19: Session 2 - Cell Wall, Biomass and
Page 26 and 27: Session 3 - Tools and Bioengineerin
Page 32 and 33: Session 4 - Biotic and Abiotic Stre
Page 42 and 43: Session 5 - Plant Development, Meta
Page 74 and 75: S: Speakers’ abstracts P: Posters
Page 76 and 77: LIST OF PARTICIPANTS 75
Page 78 and 79: BOUCHABKE-COUSSA Oumaya INRA IJPB I
Page 80 and 81: GIRALDO Patricia E.T.S.I. Agronomos
Page 82 and 83: MARION-POLL Annie INRA IJPB Institu
Page 84 and 85:
RENAULT Hugues CNRS - IBMP Institut
Page 86:
WARD Eric Two Blades Foundation, P.
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