The Fusarium mycotoxin deoxynivalenol elicits hydrogen peroxide production, programmed cell death and defence responses in wheat

Authors

  • OLIVIA J. DESMOND,

    1. CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Brisbane 4067, Australia
    2. School of Molecular and Microbial Sciences,
    3. School of Integrative Biology,
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  • JOHN M. MANNERS,

    1. CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Brisbane 4067, Australia
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  • AMBER E. STEPHENS,

    1. CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Brisbane 4067, Australia
    2. Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics,
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  • DONALD J. MACLEAN,

    1. School of Molecular and Microbial Sciences,
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  • PEER M. SCHENK,

    1. School of Integrative Biology,
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  • DONALD M. GARDINER,

    1. CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Brisbane 4067, Australia
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  • ALAN L. MUNN,

    1. Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics,
    2. School of Biomedical Sciences, University of Queensland, St Lucia, Queensland 4072, Australia and
    3. School of Medical Science, Griffith University (Gold Coast Campus), Parklands Drive, Southport, Queensland 4222, Australia
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  • KEMAL KAZAN

    Corresponding author
    1. CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Brisbane 4067, Australia
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* Correspondence:
Tel.: +61 07 3214 2678;
Fax: +61 07 3214 2920;
E-mail: kemal.kazan@csiro.au

SUMMARY

Fusarium species infect cereal crops worldwide and cause the important diseases Fusarium head blight and crown rot in wheat. Fusarium pathogens reduce yield and some species also produce trichothecene mycotoxins, such as deoxynivalenol (DON), during infection. These toxins play roles in pathogenesis on wheat and have serious health effects if present in grain consumed by humans or animals. In the present study, the response of wheat tissue to DON has been investigated. Infusion of wheat leaves with DON induced hydrogen peroxide production within 6 h followed by cell death within 24 h that was accompanied by DNA laddering, a hallmark of programmed cell death. In addition, real-time PCR analysis revealed that DON treatment rapidly induced transcription of a number of defence genes in a concentration-dependent manner. Co-treatment with DON and the antioxidant ascorbic acid reduced these responses, suggesting their induction may be at least partially mediated by reactive oxygen species (ROS), commonly known to be signalling molecules in plants. Wheat defence genes were more highly expressed in wheat stems inoculated with a DON-producing fungal strain than those inoculated with a DON-non-producing mutant, but only at a late stage of infection. Taken together, the results are consistent with a model in which DON production during infection of wheat induces ROS, which on the one hand may stimulate programmed host cell death assisting necrotrophic fungal growth, whereas, on the other hand, the ROS may contribute to the induction of antimicrobial host defences.

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