In the aftermath of both world wars, the disposal of Chemical Weapons was insufficiently documented and controlled. In Germany alone, remnants of chemical weapons are suspected in over 200 locations.

However, tracing them is difficult because the exact location and the dangers cannot beclearly determined. This year’s iGEM Team Bielefeld-CeBiTec has made it their mission to address this problem with a plant-based detection system for chemical weapon degradation products. In our project, we engineer a tobacco plant, which is capable of specifically detecting chemicals and indicating their presence by changing its colour. 

Therefore, we adapt our signalling cascade from a plant based TNT detection system developed by Antunes et al., 2011. For specific detection of chemical weapon degradation products, we engineer a Ribose Binding Protein (RBP)-based receptor, which is exported to the apoplast where it binds its ligand.

The receptor-ligand complex activates a fusion protein, consisting of a transmembrane protein and an intracellular histidine kinase. Upon activation, the kinase phosphorylates a transcription factor, resulting in expression of reporter genes.

To achieve a strong visual signal, we establish two different reporter systems with similar outcomes - a bright red plant. The red colour results from either betalains or anthocyanins. The biosynthesis of betalains is activated by expression of RUBY (He et al., 2020). For the production of anthocyanins, we develop a new reporter system based on the expression of three different transcription factors.

In the future, our plant can be easily modified  by replacing the specific receptor. This would allow the detection of additional chemical contaminants. In this way, we want to establish GMO plants as a part of our everyday life for the future to make the world a little safer and to protect it from further invisible dangers.

References:

1. Antunes, M.S., et al, 2011, PLOS ONE 6(1): e16292.
2. He, Y., et al, 2020, Horticulture Research 7, 1-6.