Team:UNILausanne
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The Problem
We Are Addressing.
Plastered in the news this spring was the story of a devastating agricultural loss in our region – the frost destroyed budding flowers on all our apricot trees, depriving us from this wonderful fruit. This crop is extremely important to Valais, a region in Switzerland close to UNIL. Not only is its successful harvest essential to the farmers financially, but it is also a pivotal part of our Swiss summer traditions and culture.
Our team was heartbroken by the loss of this year’s crop, and we made it our iGEM mission to find a solution to protect the apricot trees during prospective freezing spells. Addressing this problem is particularly urgent, as climate change promises harsher weather and therefore more significant losses in upcoming years.
The Concept
Behind Our Project.
We attacked this problem on two fronts. The first is to protect the sensitive plant tissues of apricot trees from deterioration caused by ice crystals. To do this, we created a liquid solution containing antifreeze proteins (AFPs). The second is to reduce the damage done by a plant pathogen, Pseudomonas syringae, during freezing spells. These bacteria produce ice nucleation proteins (INPs) which facilitate ice crystal formation, and strongly increase damage at temperatures below the freezing point of water. We designed two differing methods to mitigate the harm done by this pathogen.
Our Solution.
AFPs
- To diminish ice crystal damage
When the temperature drops below zero, plant tissues start deteriorating. Ice crystals wreck cells, sometimes destroying sensitive organs, such as flowers and young fruit, completely. To prevent such damage from happening to our apricot trees, we created a solution containing AFPs. These proteins bind to ice crystals, inhibiting their growth, and therefore diminishing the harm done to the plant. We thoroughly tested our solution, proving that our AFPs have a protective effect against freezing on a plant model organism at sub-zero temperatures.
Tailocins
- To prevent damage from P. syringae
Our first method of combating this pathogen was to simply eliminate it from the surface of the plants. To do so, we produced tailocins, toxins produced by bacteria to kill competitive bacterial strains. The use of these protein complexes would allow us to kill P. syringae specifically, without harming other bacterial species present in the environment.
Phages
- To prevent damage from P. syringae
Our second approach to fight this pathogen was to inactivate its InaZ gene, which encodes the ice nucleation protein. By doing so, we would inhibit the synthesis of the INP in the first place, thus rendering P. syringae harmless at low temperatures. To achieve the gene deletion, we designed a CRISPR/Cas9 system to be delivered by a phage.