The role of secondary metabolites in the interaction of plants and insects

Protection of crops against insects can use either direct host plant resistance or biological control. These two approaches are fundamentally different in that host plant resistance depends on direct defence traits of the crop plants (such as trichomes, toxic secondary metabolites or proteins, and repellents), whereas biological control depends on antagonists or enemies of the pest organisms.

For the latter it is crucial that the biological control agents are able to find their prey. Hereto, plants – upon herbivory - produce volatiles that are attractive to the natural enemies of the herbivore. The use of predators and parasitoids for biological control is receiving more and more attention and for many years it has been common practice in a number of crops in glasshouse as well as open fields. We are interested in the role of terpenes in this indirect as well as in direct defence.

Our approach:

We focus our work on the cloning and characterisation of genes involved in terpene biosynthesis and the use of these genes to modify terpene production in transgenic plants. We use model plant species such as Arabidopsis, tomato, tobacco and cucumber. We use sophisticated engineering approaches through which we also gain insight in regulation of terpene biosynthesis and subcellular compartmentation and transport. We study the molecular and biochemical consequences of the engineering and the effects on the behaviour of natural enemies as well as pest insects. Our successful modification of arabidopsis to produce an important signalling molecule, hence becoming atttractive to predatory mites, was published in Science (Kappers et al., 2005). For a review of our other metabolic engineering work see: Aharoni et al., 2005.