Priming defense genes and metabolites in hybrid poplar by the green leaf volatile cis-3-hexenyl acetate

Authors

  • Christopher J. Frost,

    1. Center for Chemical Ecology, Pennsylvania State University, University Park, PA 16802 USA;
    2. Department of Entomology, Pennsylvania State University, University Park, PA 16802 USA;
    3. School of Forest Resources, Pennsylvania State University, University Park, PA 16802 USA;
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  • Mark C. Mescher,

    1. Center for Chemical Ecology, Pennsylvania State University, University Park, PA 16802 USA;
    2. Department of Entomology, Pennsylvania State University, University Park, PA 16802 USA;
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  • Christopher Dervinis,

    1. School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611 USA
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  • John M. Davis,

    1. School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611 USA
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  • John E. Carlson,

    1. Center for Chemical Ecology, Pennsylvania State University, University Park, PA 16802 USA;
    2. School of Forest Resources, Pennsylvania State University, University Park, PA 16802 USA;
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  • Consuelo M. De Moraes

    1. Center for Chemical Ecology, Pennsylvania State University, University Park, PA 16802 USA;
    2. Department of Entomology, Pennsylvania State University, University Park, PA 16802 USA;
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Author for correspondence:
Christopher J. Frost
Tel: +1 814 441 9500
Fax: +1 814 865 3048
Email: cfrost@psu.edu

Summary

  • • Herbivore-induced plant volatiles (HIPVs), in addition to attracting natural enemies of herbivores, can serve a signaling function within plants to induce or prime defenses. However, it is largely unknown, particularly in woody plants, which volatile compounds within HIPV blends can act as signaling molecules.
  • • Leaves of hybrid poplar saplings were exposed in vivo to naturally wound-emitted concentrations of the green leaf volatile (GLV) cis-3-hexenyl acetate (z3HAC) and then subsequently fed upon by gypsy moth larvae. Volatiles were collected throughout the experiments, and leaf tissue was collected to measure phytohormone concentrations and expression of defense-related genes.
  • • Relative to controls, z3HAC-exposed leaves had higher concentrations of jasmonic acid and linolenic acid following gypsy moth feeding. Furthermore, z3HAC primed transcripts of genes that mediate oxylipin signaling and direct defenses, as determined by both qRT-PCR and microarray analysis using the AspenDB 7 K expressed sequence tags (EST) microarray containing c. 5400 unique gene models. Moreover, z3HAC primed the release of terpene volatiles.
  • • The widespread priming response suggests an adaptive benefit to detecting z3HAC as a wound signal. Thus, woody plants can detect and use z3HAC as a signal to prime defenses before actually experiencing damage. GLVs may therefore have important ecological functions in arboreal ecosystems.

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