Capsaicin is the substance that makes chili peppers spicy. It works by activating specific nerve cells in your tongue, which signal to the brain a pain caused by heat or spiciness. This is why even a tiny piece of chili pepper can set your mouth on fire. Biting into a tomato has never had the same effect, but if genetic manipulation has anything to say about it that will change soon. In the Trends in Plant Science magazine, researchers reveal that tomatoes contain everything that's needed for producing capsaicin, and current gene technology makes it possible to enable this latent ability.
While spicy tomatoes will be an interesting novelty with great potential for pranks, researchers are actually more interested in the scientific potential. They see the genetically modified spicy tomato as a good solution for large-scale capsaicin production. The substance has medical applications with its antibacterial properties and is used in painkillers. The pepper spray used by law enforcement in many countries also contains capsaicin. High concentrations have an irritable effect on the respiratory system and eyes.
It's not a huge surprise that tomatoes have the genes for producing capsaicin. Peppers and tomatoes are distant relatives. They have a common ancestor that existed around 19 million years ago and still share a lot of DNA. While tomatoes contain the genes for producing capsaicin, they currently lack the necessary mechanisms to activate these genes. Modern genetic techniques can therefore help. "In theory, you can use those genes to produce capsaicin in tomatoes," says researcher Agustin Zsögön. However, more research is needed. They have to identify which exact genes must be activated in order for the tomato to produce capsaicin. "For example, you can activate all candidate genes simultaneously and see what happens and which substances are produced. We are now trying that, along with some other methods."
Aside from being a potentially easier and cheaper source of capsaicin, the researchers also hope to learn more about how chili peppers evolved into the spicy vegetables we know today. And who knows, maybe their research will lead to new exotic vegetable varieties you can eat.