Jasmonate-deficient plants have reduced direct and indirect defences against herbivores |
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Authors: | Jennifer S. Thaler,Mohamed A. Farag,Paul W. Paré , Marcel Dicke |
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Affiliation: | Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada;Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA;Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, the Netherlands |
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Abstract: | Plants employ a variety of defence mechanisms, some of which act directly by having a negative effect on herbivores and others that act indirectly by attracting natural enemies of herbivores. In this study we asked if a common jasmonate‐signalling pathway links the regulation of direct and indirect defences in plants. We examined the performance of herbivores (direct defence) and the attraction of natural enemies of herbivores (indirect defence) to wild‐type tomato plants and mutant plants that are deficient in the production of the signalling hormone jasmonic acid. Wild‐type plants supported lower survivorship of caterpillars compared with jasmonic acid‐deficient plants. Damaged wild‐type plants were more attractive to predaceous mites compared with undamaged wild‐type plants, whereas damaged jasmonate‐deficient plants were not more attractive to predators. Damaged wild‐type plants induced a greater production of volatile compounds (primarily the sesquiterpene β‐caryophyllene and the monoterpenes α‐pinene, β‐pinene, 2‐carene and β‐phellandrene) compared with damaged jasmonate‐deficient plants. Treating jasmonate‐deficient plants with exogenous jasmonic acid restored both the direct and indirect defence capabilities, demonstrating that jasmonic acid is an essential regulatory component for the expression of direct and indirect plant defence. |
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Keywords: | Direct defence indirect defence induced resistance jasmonate-deficient jasmonate Lycopersicon esculentum Phytoseiulus persimilis plant–insect interactions Spodoptera exigua tritrophic interactions |
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