Project

Discipline

plant defense; herbivore counter defense; plant-insect interactions; secondary metabolites; benzoxazinoids; Zea mays; Spodoptera frugiperda; pest control; detoxification

Lead
Lay summary
To ward off an attack by herbivorous insects, plants produce a variety of toxic or repulsive compounds. However, specialized insects have developed counter-strategies to deal with these defence compounds, which explains why many of these insects have become agricultural pests. It is becoming increasingly clear that these plant-insect interactions can only be understood by investigating the function of plant toxins from the perspective of the plant and the insect simultaneously. In a preliminary study carried out in the FARCE laboratory at the University of Neuchâtel, we have demonstrated that benzoxazinoids (BXDs), a specific class of nitrogen-containing secondary metabolites produced by grasses, strongly affect the metabolism, the behaviour and the fitness of an important, highly specialized pest of maize: caterpillars of the moth Spodoptera frugiperda. We have found that maize changes its BXD production after detecting caterpillar feeding, and that Spodoptera frugiperda has evolved mechanisms to circumvent their negative effects. The BXD-mediated interaction between maize and Spodoptera caterpillars complex an ideal model to study the role of plant secondary metabolites at the interface between plants and insects. The current project brings together knowledge from molecular biology, plant and insect biochemistry, phytochemistry, ecology and behaviour, as well as agricultural sciences to track the fate of BXDs from their production in the plant to their conversion inside the target insect. By using such a highly interdisciplinary, cross-species approach we will be able to elucidate the precise role of BXDs in plant-insect interactions. As BXDs consume a significant fraction of the nitrogen available to a plant, but at the same time serve as a potentially important barrier against pests, our study goes beyond purely fundamental research and opens up interesting possibilities for application in agriculture. The project is headed by UniNE, represented by the FARCE laboratory and the Analytical Chemistry Service of the Swiss Plant Science Web, and involves partners from the Federal Research Station Agroscope Changins-Wädenswil, the University of Geneva and the Max Planck Institute for Chemical Ecology in Jena (Germany).

Direct link to Lay Summary

Last update: 21.02.2013

Active participation

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In order to grow and develop, many organisms, including insect herbivores, have to ingest and convert plant metabolomes to suit their own nutritional needs. A widespread counter-strategy of plants is to resist herbivory by producing toxic or inhibitory secondary metabolites. It is becoming increasingly clear that the plant metabolism responds dynamically to insect feeding, and specialized insects in turn have evolved mechanisms to quickly counteract these chemical defense responses in host plants, which leads to interdependent, iterative metabolic interactions. To determine the actual metabolic drivers of the interactions between plants and insects, it is therefore necessary to investigate their metabolism simultaneously. Because this can only be achieved within an interdisciplinary approach, few attempts have been made in this direction.Here, we propose to study benzoxazinoid derivatives (BXDs), an important class of nitrogen-containing defensive secondary metabolites in maize (Zea mays) in both plants and insect herbivores. Our unpublished results show that BXDs represent an ideal pilot model to investigate the plant-insect interface, as they react dynamically to insect attack in planta and are actively influencing the metabolism, behavior and fitness of lepidopteran maize pests, including Spodptera frugiperda and Ostrinia nubilalis. Biosynthetic mutants and genomic sequence databases are available for both plants and herbivores, making it possible to use targeted genetic manipulation to understand the system in depth. Because of the apparent potential of BXDs to reduce leaf damage by insects, they are not only of considerable interest for a fundamental understanding of plant-insect ecology, but also for application in agriculture. The project unites the expertise of the University of Neuchâtel (Chemical Ecology and Behavior; Subproject A), the agricultural research station Agroscope Changins-Wädenswil (Agroecology & Pest Control; Subproject B), the University of Geneva and the Chemical Analytical Service of the Swiss Plant Science Web (Analytical Chemistry, Subproject C) and the Max Planck Institute of Chemical Ecology (Biochemistry and Molecular Biology; Subproject D). Investigating the metabolism and ecological consequences of BXDs in maize and herbivores simultaneously will enable us to:i) Construct a detailed, dynamic metabolic map of BXDs at the plant insect interface ii) Analyze and manipulate the biochemistry of the observed metabolic changesiii) Investigate their impact on plant and insect behavior iv) Assess the potential of exploiting BXDs for pest controlWe expect that our project will contribute significantly to the advancement of the understanding of an important frontier in plant-insect interactions. The proposed approach will furthermore serve as a template for future research on interspecific metabolomics studies and may lead to the identification of target metabolites for breeding for plant resistance. Several early career scientists have been the driving force behind the development of this project, guaranteeing its contribution to capacity building and research networking within Switzerland.