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Systemic root signalling in a belowground, volatile-mediated tritrophic interaction

Ivan Hiltpold, Matthias Erb, Christelle Aurélie Maud Robert & Ted Turlings

Résumé Plants attacked by leaf herbivores release volatile organic compounds (VOCs) both locally from the wounded site and systemically from non-attacked tissues. These volatiles serve as attractants for predators and parasitoids. This phenomenon is well described for plant leaves, but systemic induction of VOCs in the roots has remained unstudied. We assessed the spatial and temporal activation of the synthesis and release of (E)-beta-caryophyllene (E beta C) in maize roots upon feeding by larvae of Diabrotica virgifera virgifera, as well as the importance of systemically produced E beta C for the attraction of the entomopathogenic nematode Heterorhabditis megidis. The production of E beta C was found to be significantly stronger at the site of attack than in non-attacked tissues. A weak, but significant, increase in transcriptional activity of the E beta C synthase gene tps23 and a corresponding increase in E beta C content were observed in the roots above the feeding site and in adjacent roots, demonstrating for the first time that herbivory triggers systemic production of a volatile within root systems. In belowground olfactometers, the nematodes were significantly more attracted towards local feeding sites than systemically induced roots. The possible advantages and disadvantages of systemic volatile signalling in roots are discussed.
   
Mots-clés Diabrotica virgifera virgifera, Heterorhabditis megidis, belowground, tritrophic interaction, entomopathogenic nematode, induced plant, defence, systemic root response, volatile emission, Western corn, rootworm, induced plant volatiles, larvae delia-radicum, entomopathogenic, nematodes, heterorhabditis-megidis, vascular pathways, brassica-oleracea, indirect defense, maize, herbivores, resistance
   
Citation Hiltpold, I., Erb, M., Robert, C. A. M., & Turlings, T. (2011). Systemic root signalling in a belowground, volatile-mediated tritrophic interaction. Plant Cell and Environment, 34(8), 1267-1275.
   
Type Article de périodique (Anglais)
Date de publication 2011
Nom du périodique Plant Cell and Environment
Volume 34
Numéro 8
Pages 1267-1275