Team:KU Leuven/Project

Our goal is to create a sustainable system to reduce the damage that aphids cause to our agricultural industry and reduce the use of insecticides.

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 BanAphids (meaning ‘to ban aphids’ as well as provide plants 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.

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

In the first system, our honeydew system, 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 aphid habituation.

We devised a second system with input from the private end user: the sticker system. Our second method starts from the principle that the BanAphids may not come in direct contact with the plants because of safety and ethical concerns. For this we turned to the sticker model 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 that the volatile pheromones it produces still pass. The Groningen 2012 iGEM team has already investigated the biosafety of this sticker. However this means the BanAphids lose direct contact with the honeydew and the Honeydew System fails. To overcome this and permit this containment, we designed our own oscillating system so that there is an alternating MeS and EBF production.

Finally we want to define the impact of both these systems on the ecosystem. In collaboration with the relevant industries we performed various plant and insect experiments for the E. coligy part of our project. This allows us to demonstrate the effect of our systems on the ecosystem.