Team:KU Leuven

Since the world population keeps on growing and all people need to be fed, it’s important that crop yields are optimized. Different factors ranging from weather to diseases and pests have a huge impact on food supplies worldwide. An example of one of these factors are aphid pests, these can lead to yield losses worth millions of dollars! Aphids, little insects belonging to the family of Aphididae, can be found everywhere: ranging from crop fields to fruit trees and even in vegetable and flower gardens. Farmers try to control them by using insecticides, but these harm the environment and aphids can become resistant to them quite rapidly. This is why we, the KU Leuven iGEM 2013 team, created an ecological insecticide-free aphid controlling mechanism, which mimics natural signalling systems used by both plants and insects.

Our bacteria are called BanAphids and produces two pheromones. The first one is methylsalicylate, which plays a role in a plant’s defence response and is produced by the plant upon infestation. The second pheromone is β-farnesene, which is an aphid alarm pheromone. In our system the BanAphids produce β-farnesene to repel aphids, while the methylsalicylate is meant to attract their natural predators such as ladybugs. We proved the functionality of these pheromones by performing insect experiments at two companies, Biobest and PC Fruit. Both companies were very interested in the concept of our project.
We designed two systems in which E. coligy can be incorporated. In the first system bacteria are sprayed on the plants and in this case the production of pheromones is dependent on the presence of aphids. This system avoids the habituation of aphids by only becoming active in the presence of aphids. The second system consists of a sticker containing E. coligy, that can be attached to a plant. In this system the production of both pheromones is alternated by the use of our own designed oscillating system. This oscillator was very extensively modelled by our team.