Signal signature of aboveground-induced resistance upon belowground herbivory in maize

Authors

  • Matthias Erb,

    1. Laboratory for Fundamental and Applied Research in Chemical Ecology (FARCE), University of Neuchâtel, Switzerland
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  • Victor Flors,

    1. Biochemistry and Plant Biotechnology Laboratory, Department CAMN, Universitat Jaume I, Castellón, Spain
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  • Danielle Karlen,

    1. Laboratory for Fundamental and Applied Research in Chemical Ecology (FARCE), University of Neuchâtel, Switzerland
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  • Elvira De Lange,

    1. Laboratory for Fundamental and Applied Research in Chemical Ecology (FARCE), University of Neuchâtel, Switzerland
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  • Chantal Planchamp,

    1. Laboratory for Biochemistry and Molecular Biology, University of Neuchâtel, Switzerland
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  • Marco D’Alessandro,

    1. Laboratory for Fundamental and Applied Research in Chemical Ecology (FARCE), University of Neuchâtel, Switzerland
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  • Ted C. J. Turlings,

    Corresponding author
    1. Laboratory for Fundamental and Applied Research in Chemical Ecology (FARCE), University of Neuchâtel, Switzerland
      *(fax +44 (0) 1582 760 981; e-mail jurriaan.ton@bbsrc.ac.uk; e-mail ted.turlings@unine.ch).
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  • Jurriaan Ton

    Corresponding author
    1. Department of Biological Chemistry, Rothamsted Research, Harpenden, Hertforshire, UK
      *(fax +44 (0) 1582 760 981; e-mail jurriaan.ton@bbsrc.ac.uk; e-mail ted.turlings@unine.ch).
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*(fax +44 (0) 1582 760 981; e-mail jurriaan.ton@bbsrc.ac.uk; e-mail ted.turlings@unine.ch).

Summary

Plants activate local and systemic defence mechanisms upon exposure to stress. This innate immune response is partially regulated by plant hormones, and involves the accumulation of defensive metabolites. Although local defence reactions to herbivores are well studied, less is known about the impact of root herbivory on shoot defence. Here, we examined the effects of belowground infestation by the western corn rootworm Diabrotica virgifera virgifera on aboveground resistance in maize. Belowground herbivory by D. v. virgifera induced aboveground resistance against the generalist herbivore Spodoptera littoralis, and the necrotrophic pathogen Setosphaeria turcica. Furthermore, D. v. virgifera increased shoot levels of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), and primed the induction of chlorogenic acid upon subsequent infestation by S. littoralis. To gain insight into the signalling network behind this below- and aboveground defence interaction, we compiled a set of 32 defence-related genes, which can be used as transcriptional marker systems to detect activities of different hormone-response pathways. Belowground attack by D. v. virgifera triggered an ABA-inducible transcription pattern in the shoot. The quantification of defence hormones showed a local increase in the production of oxylipins after root and shoot infestation by D. v. virgifera and S. littoralis, respectively. On the other hand, ABA accumulated locally and systemically upon belowground attack by D. v. virgifera. Furthermore, D. v. virgifera reduced the aboveground water content, whereas the removal of similar quantities of root biomass had no effect. Our study shows that root herbivory by D. v. virgifera specifically alters the aboveground defence status of a maize, and suggests that ABA plays a role in the signalling network mediating this interaction.

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