Tomatoes were made into sweets with genetic scissors

Basic rule is that the smaller the tomato, the sweeter it tastes. If the plant injects energy to increase the size of the fruit, less energy is needed to manufacture sugars.

However, a study in the scientific journal Nature shows how even large-sized tomatoes can get the much-needed sweetness. The trick is done with the so-called gene scissors with crispr technology.

of China Researcher at the Academy of Agricultural Sciences Jinzhe Zhang and his colleagues studied the genome of different varieties and found two genes affecting sweetness.

Both genes slcdpk27 and -26 produce proteins that suppress the plant’s sugar production. So genes are a kind of sweet brake.

When the researchers removed the brakes by disabling the genes using the crispr method, they created a sweeter fruit than before.

The amount of glucose and fructose increased by up to 30 percent of what it is in the unmodified variety. Test tasters also noticed the difference.

Gene bridge engineered tomatoes had two additional advantages. First, gene silencing did not reduce yield or tomato weight at all. When earlier attempts have been made to develop sweeter varieties, the yield has suffered.

Tomatoes also developed fewer and smaller seeds, which the researchers say is likely to appeal to consumers. However, the small size and small number did not impair the condition of the seeds or germination.

The genetically edited Moneymaker tomatoes are not quite as sweet as some cherry tomatoes. But it is possible to increase the sweetness even more.

“There are still many important sugar-regulating genes waiting to be discovered,” Zhang says for New Scientist magazine.

The researchers are working with some companies to develop commercial varieties by turning off the genes they discovered.

Stateside a transgenic purple tomato variety that produces more healthy antioxidants than usual was approved for sale last year.

Two genes from a plant called lijonankita were added to the tomato, thanks to which the variety produces anthocyanins that also give blueberries their blue color. It was about traditional gene editing.

In the Chinese study, the sweetness was increased with genetic scissors, which do not bring in new genes from outside. The function of the plant’s own genes was only changed.

Hundreds of food plants improved by genetic scissors have been developed or are being developed in plant biotechnology laboratories around the world.

In Japan, genetically edited tomatoes with more gamma-aminobutyric acid, or gaba, have already reached stores. In the country, it is believed that gaba lowers blood pressure and provides other health benefits.

European in the union, gene scissor is still subject to strict regulations regarding genetic modification, and they make it difficult to grow and sell food products developed with the method.

However, at the beginning of 2024, the European Parliament exempted gene scissors from strict GMO regulations. The member states still have to approve the parliament’s decision before it enters into force.

Published in Tiede magazine 1/2025