Escherichia coli

As all BioBricks submitted to the iGEM registry are designed to work in the model organism Escherichia coli we utilised this microorganism to allow us to clone our gene constructs successfully, ensuring our parts would be available for use by future iGEM teams. E. coli proved useful as a chassis as it has a rapid doubling time of less than an hour, this allowed cultures to be saturated O/N and a mini-prep and diagnostic gel run the following day, allowing for swift transformation into our second chassis Agrobacterium tumefaciens. The E. coli K12 strain which we utilised to clone our constructs is a biosafety level 1 organism, therefore poses minimal threat as cannot thrive in the gut.

Agrobacterium tumefaciens

A. Tumefaciens proved vital as a chassis organism in this project as acted as a shuttle chassis for the delivery of our Level 1 and Level 2 DNA constructs, once cloned in E. coli and DNA purified into the plant species and our final biosensor organism Nicotiana benthamiana. Agrobacterium tumefaciens infects plants through its Ti plasmid. The Ti plasmid inserts a segment of its DNA, termed T-DNA, into the host organisms genome when the T-DNA is successfully integrated this causes the expression of the gene of interest by the plant. Below are three cartoons showing a simplified version of Agrobacterium tumerfaciens transfection.

Nicotiana benthamiana

N. benthamiana is a widely used experimental plant from the solanaceous group of flowering plants that includes tomatoes, potatoes and capsicums. It is widely used in plant pathology due to the large number of plant pathogens (viruses, bacteria, fungi, oomycetes etc) that can successfully infect it. Of importance to synthetic biologists, N. benthamiana, is easily genetically transformed, regenerated and amenable to facile methods for virus-induced gene silencing and transient protein expression including the production of therapeutic compounds and pharmaceuticals. We selected it as the plant biosensor as it is a model organism for the plant world.