Savants Crack Genetic Code To Produce Bigger, Sweeter Tomatoes

For decades, farmers have faced a trade-off between size and flavor when growing tomatoes and eggplants.

By modifying these genes, the first group grew larger tomatoes, while the second developed sweeter variants.

The hefty tomatoes stacked in supermarkets may be impressive in size, but many consumers lament their lack of flavor. Meanwhile, smaller, wild varieties burst with sweetness but remain impractical for large-scale farming.

Now, scientists say they have cracked the genetic code to finally get the best of both worlds, ZME Science’s Tudor Tarita reported.

A pair of recent studies—one led by researchers at Johns Hopkins University and Cold Spring Harbor Laboratory and another by scientists at the Agricultural Genomics Institute in China—reveal key genes that govern both the size and sugar content of tomatoes.

By modifying these genes, the first group grew larger tomatoes, while the second developed sweeter variants.

This breakthrough could reshape global agriculture by making tomatoes and eggplants more appealing to both farmers and consumers. For the Johns Hopkins study, researchers mapped the genomes of 22 crops in the nightshade family, including tomatoes, potatoes, and eggplants.

“Over tens of millions of years, there’s been a constant churn of DNA sequences being added and lost,” said Michael Schatz, a geneticist at Johns Hopkins.

One of the gene duplicates, called CLV3, was found to influence fruit size. By using CRISPR-Cas9 gene-editing technology, scientists tweaked copies of the gene in the forest nightshade, a species native to Australia.

When only one copy was edited, the result was larger, more uniform fruit.

They also examined an African eggplant species and identified a gene called SaetSCPL25-like, which controls the number of seed cavities, or locules, inside the fruit. More locules meant bigger eggplants.

While the Johns Hopkins study focused on size, a separate team in China tackled another major issue—flavor.

Scientists at the Agricultural Genomics Institute in Shenzhen discovered two genes that act as “sugar brakes” in tomatoes, limiting their sweetness during ripening. While wild tomatoes naturally produce small, intensely sweet fruit, the cultivated varieties grown for commercial use prioritize size and yield instead.

While the Johns Hopkins study focused on size, a separate team in China tackled another major issue—flavor.

Scientists at the Agricultural Genomics Institute in Shenzhen discovered two genes that act as “sugar brakes” in tomatoes, limiting their sweetness during ripening. While wild tomatoes naturally produce small, intensely sweet fruit, the cultivated varieties grown for commercial use prioritize size and yield instead.