Marcel Dicke

Research Marcel Dicke

We investigate herbivore-induced plant volatiles that affect plant-insect interactions. This is done through different approaches including analyses of (1) transcriptomic changes, (2) metabolomic changes, and (3) ecological changes that result from herbivory.
Martin de Vos and Vivian van Oosten have compared the global changes in gene expression pattern in Arabidopsis thaliana in response to feeding damage by three herbivorous insects (the caterpillar Pieris rapae, the aphid Myzus persicae and the thrips Frankliniella occidentalis) or infection with two pathogenic microorganisms (Alternaria brassicicola and Pseudomonas syringae). This was complemented with phytohormone analyses. Each attacker induced its own phytohormone profile as well as transcriptome profile. Individual phytohormones cannot fully explain the transcriptomic changes. Most likely intensive crosstalk between signal transduction pathways influences transcriptomic changes (De Vos, Van Oosten et al. 2005, MPMI 18: 923-937).
Herbivory results in the induced production of terpenoids in many plants, including Arabidopsis and cucumber. Iris Kappers and Ludo Luckerhoff, in collaboration with our colleagues at Plant Research International have investigated the role of these terpenoids and the underlying biosynthetic genes. A linalool/nerolidol synthase gene was introduced into Arabidopsis by targetting the protein to the mitochondria, which resulted in the emission of the terpenoid (3S)-(E)-nerolidol and its derivative 4,8-dimethyl-1,3(E),7-nonatriene. In subsequent behavioural tests in an olfactometer and a multiplant setup predatory mites were tested. These predators feed on spider mites that induce the emission of the two terpenes in various plants. Predators were attracted to transgenic plants that emitted the terpenoids while they were not attracted to wildtype plants. This study shows how linking molecular genetics to metabolite analysis and behavioural assays can identify the function of a gene at different levels of biological integration (Kappers, Aharoni et al. 2005, Science 309: 2070-2072). The data are used to develop novel ways of pest control.
William Tinzaara completed his PhD-thesis on the use of an aggregation pheromone of the banana weevil. In field experiments he evaluated a ‘lure and kill’ system that combines the aggregation pheromone with the entomopathogenic fungus Beauveria bassiana. The data show that this autodissemination system has promise for a contribution to control a major banana pest.

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