A team of researchers from NUI Galway and the Federal University of Viçosa in Brazil has had their opinion article published in the international journal Trends in Plant Science, proposing to use gene editing technology for the production into tomatoes of capsaicinoids, the spicy compound found in chilli peppers.
Co-author of the article, Dr Ronan Sulpice from Plant and Botany Science, Ryan Institute at NUI Galway, said: “All genes necessary for the production of capsaicinoids are already present in tomatoes. However, they are silent, and we are proposing to activate them using gene editing technology. However, the challenge is massive because the pathway responsible for the synthesis of these compounds is very complex, so we are very likely far from the day we will consume spicy tomatoes.”
Senior author of the article, Dr Agustin Zsögön at the Federal University of Viçosa, Brazil, said: “Engineering the capsaicinoid genetic pathway to the tomato would make it easier and cheaper to produce this compound, which has very interesting applications. We have the tools powerful enough to engineer the genome of any species; the challenge is to know which gene to engineer and where.”
Spicy tomatoes could be commercialised for food consumption, but the main aim is to use them as biofactories for capsaicinoids production towards industrial uses. The rationale is that tomatoes are much more yielding than peppers, with up to 110 tonnes of fruits per hectare compared to around 3 tonnes per hectare, and have more stable yields. As a result, tomatoes would allow a much higher production of capsaicinoids.
These spicy compounds have significant nutritional and commercial uses, such as in cancer treatment, anti-inflammatory and pain medication, and even pepper spray. Currently, efforts are ongoing in Brazil to produce the tomatoes, and first results are expected by the end of this year. If successful, the scientists are considering even more imaginative ways that tomatoes may be used to produce other high value compounds.
Importantly, this work remains hypothetical, in the context of how to regulate CRISPR gene-edited crop varieties. Switching on an already present gene using a process called mutagenesis is different from transgenesis, the introduction of foreign genes into an organism.
In 2018, the EU and the US came to opposing decisions on how to classify these newer forms of gene-edited plants. So, while the prospect of spicy tomatoes may raise the interest of some people, we are a very long way from commercially growing such varieties.
To read the full opinion article in Trends in Plant Science, visit https://www.cell.com/trends/plant-science/fulltext/S1360-1385(18)30261-9