title: Hydrogen peroxide induced by the fungicide prothioconazole triggers deoxynivalenol (DON) production by Fusarium graminearum.
abstract: BACKGROUND
  Fusarium head blight is a very important disease of small grain cereals with F. graminearum as one of the most important causal agents. It not only causes reduction in yield and quality but from a human and animal healthcare point of view, it produces mycotoxins such as deoxynivalenol (DON) which can accumulate to toxic levels. Little is known about external triggers influencing DON production.
  
  
  RESULTS
  In the present work, a combined in vivo/in vitro approach was used to test the effect of sub lethal fungicide treatments on DON production. Using a dilution series of prothioconazole, azoxystrobin and prothioconazole + fluoxastrobin, we demonstrated that sub lethal doses of prothioconazole coincide with an increase in DON production 48 h after fungicide treatment. In an artificial infection trial using wheat plants, the in vitro results of increased DON levels upon sub lethal prothioconazole application were confirmed illustrating the significance of these results from a practical point of view. In addition, further in vitro experiments revealed a timely hyperinduction of H2O2 production as fast as 4 h after amending cultures with prothioconazole. When applying H2O2 directly to germinating conidia, a similar induction of DON-production by F. graminearum was observed. The effect of sub lethal prothioconazole concentrations on DON production completely disappeared when applying catalase together with the fungicide.
  
  
  CONCLUSIONS
  These cumulative results suggest that H2O2 induced by sub lethal doses of the triazole fungicide prothioconazole acts as a trigger of DON biosynthesis. In a broader framework, this work clearly shows that DON production by the plant pathogen F. graminearum is the result of the interaction of fungal genomics and external environmental triggers.
authors.affiliation: Department Biosciences and Landscape Architecture, Ghent University College/Ghent University Association, Schoonmeersstraat 52, B-9000 Gent, Belgium. kris.audenaert@hogent.be
authors.forename: Kris
authors.initials: K
authors.lastname: Audenaert
authors.forename: Elien
authors.initials: E
authors.lastname: Callewaert
authors.forename: Monica
authors.initials: M
authors.lastname: Höfte
authors.forename: Sarah
authors.initials: S
authors.lastname: De Saeger
authors.forename: Geert
authors.initials: G
authors.lastname: Haesaert
mesh_terms: D018533:Biomass; D002374:Catalase / Q000378:metabolism; D005659:Fungicides, Industrial / Q000494:pharmacology*; D005670:Fusarium / Q000187:drug effects / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008689:Methacrylates / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010091:Oximes / Q000737:chemistry / Q000494:pharmacology; D011743:Pyrimidines / Q000737:chemistry / Q000494:pharmacology; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018709:Statistics, Nonparametric; D000073739:Strobilurins; D014230:Triazoles / Q000737:chemistry / Q000494:pharmacology; D014255:Trichothecenes / Q000494:pharmacology*; D014908:Triticum / Q000382:microbiology
chemical_list: D005659:Fungicides, Industrial; D008689:Methacrylates; D010091:Oximes; D011743:Pyrimidines; D000073739:Strobilurins; D014230:Triazoles; D014255:Trichothecenes; C550005:prothioconazole; D006861:Hydrogen Peroxide; D002374:Catalase; C007262:deoxynivalenol; C087670:azoxystrobin; C550006:fluoxastrobin
references.citation: FEBS Lett. 2004 Dec 3;578(1-2):152-6
references.pmid: 15581633
references.citation: Mol Plant Pathol. 2008 Jul;9(4):435-45
references.pmid: 18705859
references.citation: Phytopathology. 2003 Jul;93(7):891-900
references.pmid: 18943171
references.citation: J Theor Biol. 1990 Jan 23;142(2):201-21
references.pmid: 2352433
references.citation: Cell. 1994 Nov 18;79(4):583-93
references.pmid: 7954825
references.citation: Environ Microbiol. 2004 Jan;6(1):79-87
references.pmid: 14686944
references.citation: Phytopathology. 2005 Dec;95(12):1397-404
references.pmid: 18943550
references.citation: FEMS Microbiol Lett. 2006 May;258(1):102-7
references.pmid: 16630263
references.citation: Proc Natl Acad Sci U S A. 2005 Nov 15;102(46):16892-7
references.pmid: 16263921
references.citation: Annu Rev Phytopathol. 2003;41:177-98
references.pmid: 12651961
references.citation: FEBS Lett. 2007 Feb 6;581(3):443-7
references.pmid: 17250833
references.citation: Proc Natl Acad Sci U S A. 1984 Dec;81(24):8014-8
references.pmid: 6096873
references.citation: FEMS Microbiol Lett. 2009 Apr;293(2):255-62
references.pmid: 19239497
references.citation: Mycopathologia. 2002;153(2):91-8
references.pmid: 12000132
references.citation: Fungal Genet Biol. 2009 Aug;46(8):604-13
references.pmid: 19406250
references.citation: Microbiology (Reading). 2009 Sep;155(Pt 9):3149-3156
references.pmid: 19497949
references.citation: J Microbiol Methods. 2009 Mar;76(3):234-40
references.pmid: 19047000
references.citation: Fungal Genet Biol. 2008 Apr;45(4):389-99
references.pmid: 17950638
references.citation: Eur J Biochem. 2004 Jun;271(11):2264-71
references.pmid: 15153117
references.citation: Biochim Biophys Acta. 2008 Apr;1778(4):1141-7
references.pmid: 18187036
references.citation: FEMS Microbiol Lett. 2007 Oct;275(1):53-61
references.pmid: 17711459
references.citation: Mol Plant Pathol. 2004 Nov 1;5(6):515-25
references.pmid: 20565626
references.citation: FEMS Microbiol Lett. 2008 Jul;284(2):142-9
references.pmid: 18510557
references.citation: Environ Pollut. 2002;116(1):37-47
references.pmid: 11808554
references.citation: Antimicrob Agents Chemother. 1992 Aug;36(8):1626-9
references.pmid: 1329623
references.citation: Trends Microbiol. 2005 Mar;13(3):111-8
references.pmid: 15737729
references.citation: Eukaryot Cell. 2008 Aug;7(8):1352-61
references.pmid: 18567788
references.citation: J Biol Chem. 2004 Feb 20;279(8):6501-6
references.pmid: 14645222