Capsaicinoids, the chemicals that make food taste "hot", have shown promise as painkillers and are used in products like pepper spray.
The fleshy tomato stands in sharp contrast to the more agriculturally hard chilli plant that contain capsaicinoids, molecules that give peppers their spiciness.
"Engineering the capsaicinoid genetic pathway to the tomato would make it easier and cheaper to produce this compound, which has very interesting applications", said senior author Agustin Zsögön, a plant biologist at the Federal University of Viçosa in Brazil whose group is working toward this goal.
Rather than splice new genes into the tomatoes, researchers would need only activate existing genes using gene-editing tools like TALENs or the well-known CRISPR/Cas9. Tomatoes and chilli peppers developed from a common ancestor. The tomato could itself become a factory for producing capsaicinoids, or, yes, companies could just market spicy tomatoes. Having chillies activate nerve cells in the tongue that deal with heat-induced pain, which the brain interprets as a burning feeling. Meanwhile Native American horticulturalists in Mexico 6,000 years ago turned wild bird peppers into domesticated varieties that continued to produce capsaicins (the compounds that give peppers their delicious hotness).
There 23 known types of capsaicinoids and they are all believed to stem from the chilli pepper's pith. Now biotech researchers are suggesting that cooks could skip a step and simply use tomatoes engineered to produce their own pepper spice. However, the process of genetically tweaking a tomato species to generate the compound naturally is challenging and determining which genes are directly responsible for its production will take time.
Fancy a spicy tomato in your salad?
Research in the past has found that the genes required for capsaicinoid production are found in the tomato genome but the plant does not have the necessary infrastructure to activate it. "Since we don't have solid data about the expression patterns of the capsaicinoid pathway in the tomato fruit, we have to try alternative approaches". "You could produce [the capsaicinoids] in a more cost-effective manner", Zsögön said.