Tomato, Tuh-mah-toh: Turns out there IS a difference!

The age-old debate over whether tomatoes are a fruit or vegetable pales in comparison to the more pressing question: why don’t they taste as good as they used to?

Tomatoes are a staple ingredient in kitchens worldwide, but their flavour has been a subject of debate for years. While wild tomatoes boast a sweet, tangy taste, their cultivated counterparts—bred for size and yield—often fall short on flavour. But now, researchers in China have found a way to combine these components, using gene-editing technology to create tomatoes that are both large and sweet.

A team led by scientists at the Chinese Academy of Agricultural Sciences identified two genes, SlCDPK27 and SlCDPK26, which help in regulating sugar production in tomatoes. These genes, more active in larger varieties, produce proteins that inhibit the sugar-making process during ripening. In contrast, wild tomato plants, which are naturally sweeter, have less active versions of these genes. Using CRISPR-Cas9, a precise gene-editing tool, the researchers disabled these genes in a popular tomato variety called Moneymaker. The result? Tomatoes with up to 30% higher sugar content and no noticeable reduction in size or yield.

“This discovery resolves the trade-off between sweetness and yield,” said Professor Sanwen Huang, director general of the Agricultural Genomics Institute in Shenzhen. “Farmers can still grow large, high-yield tomatoes, while consumers get the sweeter taste they want.” The researchers, whose findings were published in the journal Nature, noted a few additional effects. The gene-edited tomatoes had fewer and smaller seeds—something that might even appeal to consumers—but germination rates were unaffected.

The relationship between size and sweetness has been a long-standing challenge for breeders. Larger tomatoes naturally dilute their sugar content, while efforts to boost sweetness have often led to lower yields. By targeting specific genes that act as “sugar brakes”, the researchers managed to sidestep these challenges. The gene-edited tomatoes were rated sweeter in taste tests than their unedited counterparts. While still not as sugary as cherry tomato varieties like Sungold, the edited tomatoes could reduce the need for added sugars in products like ketchup and sauces.

This discovery has the potential to reshape the market. “We’re working with companies to develop commercial varieties by knocking out these genes,” said lead researcher Jinzhe Zhang. Although still in the early stages, Huang estimates that consumers could see these tomatoes on supermarket shelves within three to five years. 

The global market for gene-edited crops is growing. In Japan, CRISPR-edited tomatoes with high levels of the beneficial nutrient GABA are already being sold. Similarly, the U.S. offers purple genetically modified tomatoes rich in anthocyanins. Unlike traditional genetic modification, gene editing focuses on precise changes to existing DNA, making it less controversial and quicker to approve in countries like China and Japan.

The potential doesn’t stop here. “There are still many important genes that regulate sugar waiting to be discovered,” Zhang said. Future developments could push sweetness levels even higher, offering new options for consumers and the food industry alike. For now, the team’s work is a promising step toward making tomatoes that balance flavour, size, and yield. As research continues, sweeter, juicier tomatoes might just become the new standard—without compromising the farmer’s bottom line.

Picture Credits: https://www.marthastewart.com/7976953/tomato-guide-varieties-eating