Team:KU Leuven/Project

Our goal is to create a sustainable system to reduce the damage that aphids cause to our agricultural industry. The current solution usually requires huge amounts of insecticides, damaging ecosystems in several ways. First, the indiscriminate weakening of insects means that beneficial insects (pollinators, ...) are also affected. Second, insecticides affect vertebrates, including humans, damaging our health. Third, insecticide residues (catabolites) accumulate in each food-chain. The highest organism, be it humans or for example predatory birds, will end up with potentially high levels of residues and their negative effects.
We aim to offer an effective and sustainable alternative for insecticides. Our modified E. coli, the BanAphid (meaning ‘to ban aphids’ as well as with ‘benefits’), would produce the aphid’s own alarm pheromone, E-β-farnesene, (EBF) to repel them off the plant. On top of that we want to attract aphid predators such as the ladybug via the production of methyl salicylate (MeS), a phytohormone, by our BanAphids. This way we ensure aphids are thoroughly removed from the plant. More about this can be found here.

We devised two different systems that might use these molecules. We did this because of response from both private end users and the general public.

In the first model, our glucose (honeydew) model, we spray our BanAphids directly onto the plants. In this system our BanAphids will only produce MeS when aphids are present because they are sensitive to the high concentrations of glucose found in the honeydew produced by the aphids. This interaction minimises the burden on the plant’s metabolism, attracts predators only when needed and avoids habituation.

Secondly, we obtained early input from the private end user and we used this to design the oscillator model which uses a special sticker. Our second method starts from the principle that the BanAphids may not come in direct contact with the plantsbecause of seafety concerns. For this we turned We turned to the sticker model of of the Groningen 2012 iGEM team to use as a container. The sticker is composed of a plastic film, whose pores are too small for the BanAphids to pass, but large enough so the volatile pheromones it produces still pass. The Groningen 2012 iGEM team has already investigated the biosafety of this sticker. However this means our system loses contact with the honeydew. To allow this containment and still avoid habituation we developed an oscillating system so that there is an alternating MeS and EBF production.

Finally we want to define the impact of both these models on the ecosystem. In collaboration with relevant industries we performed various ecosystem experiments. This allows us the demonstrate the effect of our models on both plants and insects.