Options
Turlings, Ted
Nom
Turlings, Ted
Affiliation principale
Fonction
Professeur ordinaire
Email
ted.turlings@unine.ch
Identifiants
Résultat de la recherche
2 Résultats
Voici les éléments 1 - 2 sur 2
- PublicationAccès libreSignal signature of aboveground-induced resistance upon belowground herbivory in maize(2009)
; ; ; ; Ton, JurriaanPlants 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. - PublicationAccès libreFungal Infection Reduces Herbivore-Induced Plant Volatiles of Maize but does not Affect Naïve Parasitoids(2006)
; Plants attacked by insects release volatile compounds that attract the herbivores' natural enemies. This so-called indirect defense is plastic and may be affected by an array of biotic and abiotic factors. We investigated the effect of fungal infection as a biotic stress agent on the emission of herbivore-induced volatiles and the possible consequences for the attraction of two parasitoid species. Maize seedlings that were simultaneously attacked by the fungus Setosphaeria turcica and larvae of Spodoptera littoralis emitted a blend of volatiles that was qualitatively similar to the blend emitted by maize that was damaged by only the herbivore, but there was a clear quantitative difference. When simultaneously challenged by fungus and herbivore, the maize plants emitted in total 47% less of the volatiles. Emissions of green leaf volatiles were unaffected. In a six-arm olfactometer, the parasitoids Cotesia marginiventris and Microplitis rufiventris responded equally well to odors of herbivore-damaged and fungus- and herbivore-damaged maize plants. Healthy and fungus-infected plants were not attractive. An additional experiment showed that the performance of S. littoralis caterpillars was not affected by the presence of the pathogen, nor was there an effect on larvae of M. rufiventris developing inside the caterpillars. Our results confirm previous indications that naïve wasps may respond primarily to the green leaf volatiles.