Proposed Implementation

Proposed Implementation

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Our project's end goal is to genetically engineer a strain of common wheat (T. aestivum) to increase its heat tolerance for use by farmers in agricultural land and downstream processing, shipping, and distribution for human feed. Our final product would therefore be a transgenic seed that farmers would purchase for growth in replacement of other varieties. It would be sold directly to farmers as well as promoted to crop consultants for them to advise farmers to purchase the seed, and to seed banks to keep repertoires of the seed for storage purposes.

Stakeholders

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It is important to consider what risks might come of this and how we can make the introduction of this new crop strain be done safely. We first considered who the stakeholders are in this project in order to determine potential risks with implementation; there is an extensive stakeholder pipeline analysis in our Entrepreneurship page, with the main implementation workflow pictured below. To ensure our implementation using this plan is feasible, we contacted many of our stakeholders, including farmers, consumers, and intermediaries, to gain insight on how well this would fit within their current needs and the grain market.

Our stakeholder consultations resulted in the great majority of stakeholders expressing support of our project, indicating that they would purchase, fund, or endorse a product like this. Despite this voiced support, there are concerns about Genetically Modified Organisms (GMO) being used in agriculture in manners that would affect our stakeholders ^[1-3].

Some of these concerns are:

• Possibility for new and unforeseen allergies to develop in consumers due to genetic changes in the crop.
• Pleiotropy, or the possibility of the changes we make to the plant having other effects on the plants.
• Contamination between GMO and non-GMO plants.
• Change in the taste of wheat plants.

Risk Management

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There are several strategies that could be used to reduce or prevent the risks outlined above. In parallel to the strategies below, we mitigated the risk of misuse of our technology through educating the public on the utility and nuances around GMO use, particularly in human feed. Detailed information about our GMO awareness efforts can be found on our Education & Communication page. Events like this contribute to increasing education in the community and inform farmers about the potential benefits, risks, and strategies when using GMOs. In addition to efforts done in the scope of our project and team in the iGEM timeline, we propose the following risk management strategies during the implementation of our project:

Administrative Controls

• Farmer training about GM crops and different risk management strategies.

Physical Biocontainment

Farmers already use many types of physical biocontainment when it comes to growing genetically modified crops^[4], including:

• Confined field testing of GMO crops during research trials at the recommended distance from other crops. For wheat, this distance is 2 metres during confined research trials, which we are committed to maintaining even after these trials are over and it is not a requirement anymore^[5].
• Implementing land use restrictions after planting and harvesting of GMOs. This means we would prohibit the growth of non-GMO plants on the land our crops were grown to prevent a risk of cross-contamination.
• Preventing the growth of GMO and non-GMO plants that can cross-pollinate. This means separating equipment and storage for these crops as well.
• Implementing physical barriers between GMO and non-GMO crops, such as windbreaks and hedgerows to minimise pollen drift.
• Keeping neighbour farms notified of what farms are growing GM crops.
• Stagger plantings of GMO and non-GMO crops so they don't flower at the same time and cannot cross-pollinate.

Genetic Biocontainment in Wheat

Genetic containment strategies can be added to our current design to prevent cross-contamination with non-GM crops, such as the ones below.

• Synthetic auxotrophy: engineer the plants to depend on an externally supplied compound, most likely an amino acid supplement, by knocking out the function of a gene responsible for synthesizing the compound^[6]. For example, one could make a crop dependent on threonine deaminase, an essential compound for plant growth, through knocking out the gene that produces it and only allowing it to grow when it is externally supplied. This would result in our GM wheat not being able to grow if seeds were dispersed to another farmer's lot since it would require supplementation of this amino acid for growth. Synthetic auxotrophy is a commonly employed technique for biocontainment of various crops; for wheat specifically, this could pose a slight challenge in validating due to the size and redundancy of the wheat genome, and therefore multiple copies of the gene needing to be knocked out.
• Another goal of our biocontainment would be to remove the synthetic genes after they are not needed (ie. when summer has passed). We considered strategies for this such as killswitch production and gamete excision, but choosing the inducibile stimuli of the system led us to decide against these choices. Killswitches require activation by a promoter inducible by a certain signal, however, there is no appropriate signal that would indicate the need for a killswitch in our scenario apart from the onset of winter when our system is not needed anymore^[7]. Gamete excision, where transgenic genes are excised from the organism's genome, runs into the same issue of inducibility. Ideally we would want our crop to remove the gene when winter sets for a certain harvest of wheat.
• Although there are other genetic biocontainment strategies such as cleistogamy (self-pollinating plants that don't release pollen), maternal inheritance, or total sterility, those are not viable options for the purpose of this project.
• Sterility: Since wheat seeds are what make up the edible part of wheat, sterility would result in having a non-edible wheat product.
• Maternal inheritance: refers to the ability to encode the synthetic gene expression in the chloroplast, which is inherited maternally therefore not being present in as many progeny as usual. While some factors of our construct interacted with the genes present in the wheat chloroplast genome, most factors were independent of the chloroplast entirely. This would render our system obsolete if expressed in the chloroplasts alone.

The best biosafety plan of action for the implementation of our project would be a combination of several of the strategies listed above. The physical containment strategies are well tested and used by farmers and could be paired with a genetic containment system for more effective mitigation of risks^[4].