Imperial iGEM success
Towards engineering smart and safe bacteria to fight worldwide soil erosion
It was a truly triumphant success for Imperial this November at MIT in Boston, where the iGEM world championship took place. iGEM, first launched in 2004, is the most prestigious and largest undergraduate competition in synthetic biology worldwide. Imperial has a long history of success in the competition, but the Imperial iGEM team managed to break all records this year.
The group of nine students took home a series of major prizes from both the European jamboree in Amsterdam, where they were declared regional winner, and the world championship in Boston. Despite the strong competition, Imperial was a proud finalist and 1st runner up for the final grand prize, and won the iGEMers prize as well as numerous other prizes.
With their project, the iGEM researchers have tackled the problem of world-wide soil erosion and desertification of drylands. Lacking a stabilising and anchoring root system, the nutritious soil is highly vulnerable to erosive forces, such as rain and wind. Arable land, on whose cultivation approximately two billion people depend, is being successively lost. Soil integrity is crucial to avoid the severe aggravation of food scarcity, and biodiversity loss due to the effects of climate change.
The first module, ‘Phyto-Route’ aimed at rewiring E.coli chemotaxis by introducing a malate chemoreceptor from a soil bacterium. The seeds would germinate and then secrete L(-)malic acid (malate), acting as chemoattractant, E.coli would then move towards the gradient and be actively taken up into the roots. Capillary assays have shown effective malate chemotaxis of cells containing the construct and the natural uptake by roots was demonstrated with confocal stack imaging.
With the second module, “Auxin Xpress”, the students successfully expressed the genes for Auxin expression from Pseudomonas savastanoi in E.coli. They further determined the IAA expression level of the module and the IAA concentration treshold for optimal root growth, thereby laying the basis for further fine-tuning of gene expression levels. In simulations of soil erosion (watering with hoose) and application of the optimum concentration of IAA, the team has demonstrated improvement to soil stability.
The concerns about releasing GMO to the environment were addressed by the third module, “Gene Guard”. This safety mechanism should prevent the spread of synthetic DNA to naturally abundant soil bacteria with a combination of separately existing toxins and anti-toxins, rendering the recipient cell of horizontal gene transfer non-viable and thereby minimizing the contamination risk of the natural rhizosphere. In the very short time span of a summer, the group has paved the way towards a smart and safe solution that could improve the lifes of billions of people around the globe.
Certainly, the enhanced engineering of biological systems with standardized parts, the fostering of synergies between systems and synthetic biology, and the study of ecological, human and ethical implications will continue to provide means for optimized, inspired and impactful researching-during iGEM and happily ever after.