title: Fusarium response to oxidative stress by H2O2 is trichothecene chemotype-dependent.
abstract: The present study aims at clarifying the impact of oxidative stress on type B trichothecene production. The responses to hydrogen peroxide (H(2)O(2)) of an array of Fusarium graminearum and Fusarium culmorum strains were compared, both species carrying either the chemotype deoxynivalenol (DON) or nivalenol (NIV). In both cases, levels of in vitro toxin production are greatly influenced by the oxidative parameters of the medium. A 0.5 mM H(2)O(2) stress induces a two- to 50-fold enhancement of DON and acetyldeoxynivalenol production, whereas the same treatment results in a 2.4- to sevenfold decrease in NIV and fusarenone X accumulation. Different effects of oxidative stress on toxin production are the result of a variation in Fusarium's antioxidant defence responses according to the chemotype of the isolate. Compared with DON strains, NIV isolates have a higher H(2)O(2)-destroying capacity, which partially results from a significant enhancement of catalase activity induced by peroxide stress. A 0.5 mM H(2)O(2) treatment leads to a 1.3- to 1.7-fold increase in the catalase activity of NIV isolates. Our data, which show the higher adaptation to oxidative stress developed by NIV isolates, are consistent with the higher virulence of these Fusarium strains on maize compared with DON isolates.
authors.affiliation: Department of Cell Biology and Neuroscience, University of California at Riverside, Riverside, CA, USA.
authors.forename: Nadia
authors.initials: N
authors.lastname: Ponts
authors.forename: Leslie
authors.initials: L
authors.lastname: Couedelo
authors.forename: Laetitia
authors.initials: L
authors.lastname: Pinson-Gadais
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Verdal-Bonnin
authors.forename: Christian
authors.initials: C
authors.lastname: Barreau
authors.forename: Florence
authors.initials: F
authors.lastname: Richard-Forget
mesh_terms: D002374:Catalase / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D005670:Fusarium / Q000187:drug effects* / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress; D013312:Stress, Physiological; D014255:Trichothecenes / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D005656:Fungal Proteins; D016877:Oxidants; D014255:Trichothecenes; D006861:Hydrogen Peroxide; D002374:Catalase