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Phloem-feeding whiteflies can fool their host plants, but not their parasitoids
Auteur(s)
Zhang, Peng-Jun
Xu, Cai-Xia
Zhang, Jin-Ming
Lu, Yao-Bin
Wei, Jia-Ning
Liu, Yin-Quan
David, Anja
Boland, Wilhelm
Date de parution
2013
In
Functional Ecology
Vol.
6
No
27
De la page
1304
A la page
1312
Résumé
* Herbivore attack induces plants to mobilize chemical defences, including the release of volatiles that attract natural enemies of the herbivore. This commonly involves the jasmonic acid (JA) pathway. However, phloem-feeding whiteflies specifically trigger salicylic acid (SA)-signalling, thereby suppressing JA-based defences and enhancing host plant suitability. * Here, we show with Arabidopsis thaliana plants that the whitefly parasitoid Encarsia formosa outsmarts this apparent host plant manipulation by exploiting the SA-triggered emission of ?-myrcene. Assays with various Arabidopsis mutants and phytohormone and gene-expression analyses reveal that the whiteflies induce the accumulation of endogenous SA, thereby enhancing the expression of SA-regulated genes, one of which encodes ocimene/myrcene synthase, which resulted in the recruitment of parasitoids under greenhouse conditions. Performance assays confirmed that whiteflies directly benefit from suppressing JA-based defences. * Taken together, we conclude that by activating SA-signalling whitefly feeding suppresses direct, JA-based defences, but that parasitoids can adapt to this by exploiting specific, SA-induced volatile emissions for host location. * Our work further confirms that herbivory contributes to selective pressure governing the evolution of inducible volatile signals as indirect plant defences.
Identifiants
Type de publication
journal article
