Team:Imperial College London/Project Chemotaxis Specifications
Module 1: Phyto-Route
Chemotaxis is the movement of bacteria based on attraction or repulsion of chemicals. Roots secrete a variety of compounds that E. coli are not attracted to naturally. Accordingly, we engineered a chemoreceptor into our chassis that can sense malate, a common root exudate, so that it can swim towards the root. Additionally, E. coli are actively taken up by plant roots, which will allow targeted IAA delivery into roots by our system.
1. The bacteria should actively move towards roots.
In order to do this, the bacteria need to be able to sense a common root exudate. We have chosen to rewire E. coli's chemotactic pathway towards L(-)malic acid (also referred to as malate), a compound found in the Citric acid cycle. It is secreted by the roots at low concentrations.
2. Uptake of bacteria into roots.
Uptake of bacteria into the roots followed by the secretion of natural chemicals presents a novel platform for modifying plants without genetically modifying the plant genomes.
3. Efficient expression of foreign genes in our chassis.
Since we are introducing genes from soil bacteria into E. coli we have to take into account the effect that codon bias can play in the expression of our constructs. Therefore, we have to ensure that expression of our construct is not constrained by this phenomenon.