To ward off an attack by herbivorous insects, plants employ defence strategies based on the production of repulsive or toxic substances. They produce small toxic molecules, such as alkaloids or phenolic compounds that disrupt the digestive system of insects.

 

However, specialized pest insects have managed to limit the damages over the course of evolution by chemically neutralising the toxic molecules, by quickly excreting them, or by adapting their intestines rendering them insensitive to these compounds. In order to better understand these successive reactions as on the whole, the research consortium will be specifically studying benzoxazinoid (BXD) derivatives, a class of nitrogen containing metabolites in maize.

 

In a preliminary study, Matthias Erb and Gaétan Glauser, researchers in the FARCE laboratory supervised by Ted Turlings, have demonstrated that BXD affect the metabolism, the behaviour and the fitness of an important pest of maize: caterpillars of the noctuid moth Spodoptera frugiperda. These results confirm that BXD is the ideal model to study biochemical reactions that occur at the plant-insect interface. 

 

The project is unique because it simultaneously tracks the modifications of plant and insect metabolism using a multidisciplinary approach. At the biochemical level, the researchers will examine the enzymes that are produced when the plant is attacked. They will then analyse what happens to the plant-produced toxic substances when the insects launch their counterattack. Finally, on an ecological level, the project will look at the consequences of BXD for the performance of insect herbivores, as well as for the growth and vigour of maize.

 

With the potential for BXD to reduce damages caused by insect herbivores, it is obvious that the aims of the project go beyond fundamental research and that it will reveal interesting novel strategies for application in agriculture.

 

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