Petunia hybrida PDR2 is involved in herbivore defense by controlling steroidal contents in trichomes

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• 作者：Joë ; lle Sasse ; Markus Schlegel ; Lorenzo Borghi ; Friederike Ullrich ; Miyoung Lee ; Guo-Wei Liu ; José ; -Luis Giner ; Oliver Kayser ; Laurent Bigler ; Enrico Martinoia and Tobias Kretzschmar
• 刊名：Plant, Cell & Environment
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：39
• 期：12
• 页码：2725-2739
• 全文大小：906K
• ISSN：1365-3040

文摘

As a first line of defense against insect herbivores many plants store high concentrations of toxic and deterrent secondary metabolites in glandular trichomes. Plant Pleiotropic Drug Resistance (PDR)-type ABC transporters are known secondary metabolite transporters, and several have been implicated in pathogen or herbivore defense. Here, we report on Petunia hybrida PhPDR2 as a major contributor to trichome-related chemical defense. PhPDR2 was found to localize to the plasma membrane and be predominantly expressed in multicellular glandular trichomes of leaves and stems. Down-regulation of PhPDR2 via RNA interference (pdr2) resulted in a markedly higher susceptibility of the transgenic plants to the generalist foliage feeder Spodoptera littoralis. Untargeted screening of pdr2 trichome metabolite contents showed a significant decrease in petuniasterone and petuniolide content, compounds, which had previously been shown to act as potent toxins against various insects. Our findings suggest that PhPDR2 plays a leading role in controlling petuniasterone levels in leaves and trichomes of petunia, thus contributing to herbivory resistance.