Gene modification can create bigger, better tomatoes, but should we do it?

Imagine biting into a juicier, tastier tomato or cooking with an eggplant that’s not just flavorful but also larger. Scientists have made a discovery that could bring this to reality by identifying genes that control fruit size.

Researchers at Johns Hopkins University (JHU) and Cold Spring Harbor Laboratory (CSHL) have mapped genetic sequences in tomatoes and eggplants, paving the way for the development of new, improved varieties.

Their findings, published in Nature, could transform agriculture, particularly in regions where local varieties are too small to support commercial production.

Understanding gene modification – the basics

Gene modification for plants is basically science giving nature a little upgrade. Scientists tweak plant DNA to make crops stronger, more nutritious, or resistant to pests and harsh weather.

Instead of waiting generations for traditional breeding to get the perfect traits, genetic engineering speeds up the process.

For example, some modified crops can fight off insects without needing pesticides, while others grow in salty soil or survive droughts.

In this instance, modifying the genes of tomato plants will provide bigger and better tomatoes.

This tech has already changed farming, making it more efficient and reducing the need for chemical sprays that can harm the environment.

Changing agriculture with one seed

“Once you’ve done the gene editing, all it takes is one seed to start a revolution,” said Michael Schatz, a geneticist at Johns Hopkins University and co-lead author of the study.

“With the right approvals, we could mail an engineered seed to Africa or anywhere it’s needed and open up entirely new agricultural markets. There’s huge potential to translate these advances into real-world impact.”

The study is part of a larger initiative to map the full genomes of 22 crop plants within the nightshade family, which includes tomatoes, potatoes, and eggplants.

The researchers used computational analysis to compare genetic maps and track how genes evolved. They discovered that, over time, more than half of these genes had been duplicated.

Tracing genetic changes over time

“Over tens of millions of years, there’s this constant churn of DNA sequences being added and lost,” Schatz explained.

“The same process can occur for gene sequences, where entire genes duplicate or disappear. When we started looking, we noticed these changes were very widespread, but we didn’t yet know what those changes meant for the plants.”

To answer that question, researchers at the Boyce Thomson Institute used CRISPR-Cas9 technology to edit these genes. Scientists at Cold Spring Harbor then grew the engineered plants to observe the results.

The duplicated genes, known as paralogs, turned out to be essential for traits like fruit size, shape, and flowering time.

One experiment involved turning off both copies of a gene called CLV3 in the forest nightshade, a plant native to Australia.

The result was that misshapen, “weird, bubbly, disorganized” fruits were formed. These wouldn’t be viable for grocery stores. However, tweaking just one copy of the gene led to plants with larger fruits.

Genetic treasure map for tomatoes

“Having full genome sequences for these species is like having a new treasure map,” said Katharine Jenike, who helped assemble the genome sequences as a Ph.D. student in Schatz’s lab.

“We can see where and when one genetic path diverges from another and then explore that place in the genetic information where we wouldn’t have thought to look. This allowed us to find the size-genes in a really unexpected place.”

One of the most exciting discoveries came from the African eggplant, a crop grown across Africa and Brazil. Scientists identified a gene, SaetSCPL25-like, which controls the number of seed cavities, or locules, inside the fruit.

When they edited this gene in tomatoes, they found that increasing the number of locules resulted in larger tomatoes.

Tomatoes, eggplants, and genes

These findings suggest that careful gene editing could lead to larger, more commercially viable tomatoes and eggplants.

“This work shows the importance of studying many species together. We leveraged decades of work in tomato genetics to rapidly advance African eggplants, and along the way we found entirely new genes in African eggplants that reciprocally advance tomatoes,” Schatz explained.

“We call this ‘pan-genetics,’ and it opens endless opportunities to bring many new fruits, foods, and flavors to dinner plates around the world.”

With continued research and the right regulatory steps, these discoveries could change how we grow and consume some of our favorite fruits and vegetables in the years ahead.

Future of tomato plants and gene editing

Beyond simply increasing fruit size, this research has broader implications for global agriculture.

In many parts of the world, farmers struggle with low-yield crops that are not suitable for large-scale farming.

With gene editing, scientists could tailor plants to specific environments, making them more resistant to climate change, pests, and diseases.

By using advanced genetic tools, researchers hope to create crops that not only grow larger but also require fewer resources, such water and fertilizers.

This could make farming more sustainable and reduce environmental impacts.

Future studies may focus on improving taste, nutritional value, and shelf life, which would ensure that these new varieties don’t just benefit farmers but also provide better food options for consumers.

The full study was published in the journal Nature.

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