The three day 4th New Phytologist Workshop on Synthetic Biology started on Wednesday 6th June, and we waited until after the Thursday afternoon coffee break to hear a presentation on plant synthetic biology. It was obvious that plant synthetic biology is not yet as sophisticated as synthetic chemistry and microbiology, and the reasons were implied in many of the talks. Plants are multi-cellular, have weeks-long life cycles and their products cannot simply be skimmed off or distilled from a vat of cells.
Rob Edwards (University of York) was quick to defend plant synthetic biology when I put this to him, pointing out that plant plastids are a means both of expressing a transgene and storing its possibly toxic product, all without affecting the rest of the cell. Plants can be grown cheaply, particularly if engineered to do so, although extracting the product may be expensive and difficult. On the other hand, synthetic biology may be used to enhance the flavor, fragrance or appearance of a fruit or flower and in that case the plant itself is a high-value product which requires no extraction.
While Rob Edwards’ SPPI-net focuses on synthetic biology for non-food plant products, he stated that genetically improved food crops can have great effects. Golden rice has the potential to help prevent blindness in areas where communities living on rice-based diets suffer from vitamin A deficiency, and soybean containing high omega-3 fatty acids can improve cardiovascular health.
However high value non-food products hold more interest for big industry, and multinational companies are ultimately the parties most likely to be willing to pay the huge costs involved in funding, trialing, and bringing synthetic plant products to market.
In the discussions over lunch and after presentations, it was clear that the consensus on engineered crops is that current and future research holds huge potential for easing the problems presented by increasing global demand for food and energy. It was agreed that the main obstacles preventing their use are regulations for their release, which are extremely stringent compared to other new technologies, and opposition from groups who ideologically oppose GM and are very efficient at persuading the public to support their view.
The final plant synthetic biology presentation was from June Medford, whose group in Colorado State University has developed ‘intelligent plants’ that, unlike the aggressive Triffids in John Wyndam’s apocalyptic story, are sentinels that warn people of air- or water-borne toxins. The plants contain an entirely synthetic system which includes a receptor designed to respond to a specific chemical, for example TNT, and a histadine kinase transmitter which relays the signal to the de-greening circuit via a synthetic pho-B promotor.
These plant sentinels are a fantastic example of the practical usefulness of synthetic biology, which may be the reason that the public eventually accepts synthetic bioproducts. Imagine leafy plants in homes and public spaces that go white if there is even a hint of carbon monoxide, explosive or toxic molecule in the air or water. Of course they will probably never replace guards or electronic detectors, but as a back-up when the battery in your home alarm fails or as latent sentinels in low-risk areas, they are unthreatening and effective.
Rob Edwards and June Medford’s reluctance to spend time and money on synthetic biology for food products is unsurprising given the history of GM food. They and many other synthetic biologists at the workshop know that the earliest commercial successes of synthetic biology are unlikely to be in food, despite the life-saving properties of golden rice. The unthreatening, useful plant sentinels and high-value products could be the buffer that introduces the public to the full potential of synthetic plant products.