Tomato: Cultivated from the wild

Geneschere CRISPR creates a new crop in just one generation

More and bigger fruits: The new tomato (right) has different characteristics that distinguish it from the wild plant. © Agustin Zsögön / Nature Biotechnology
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Genetic engineering makes it possible: Researchers have turned a wild plant into a crop in just one generation. With the help of the CRISPR / Cas 9 gene scissors they transformed a wild tomato species into a breeding tomato with larger fruits and more yield. The trick: unlike many of today's crops, this new tomato has at the same time retained its valuable "wild" properties such as a higher nutrient content. The method has enormous potential for agriculture, writes the team in the journal Nature Biotechnology.

Whether wheat, corn or tomato: With the invention of agriculture, humans began to grow food crops and breed them in a targeted manner. He gradually changed these plants to suit their needs. Over the course of thousands of years, crops with more and larger fruits have been created. Their wild ancestors often resemble these breeds designed for maximum yield often only remotely.

As a side effect, the breeding process leads to less genetic diversity and the loss of many useful properties - from resistance to pathogens and drought to a high vitamin and nutrient content. However, properties such as these are increasingly in demand, among other things in view of climate change and the growing world population. So what do you do?

Genetic changes

Scientists led by Augustin Zsögön of the University of Minnesota in Minneapolis have wondered if important food crops can be re-domesticated and re-domesticated - in the turbo process. They tested this using the example of tomato: In the wild species Solanum pimpinellifolium, they used the gene scissors CRISPR / Cas 9 to simultaneously modify six genes that are important for crop yield, among other things.

In this way, the South American ancestor of today's cultivated tomatoes should be made fit for agricultural cultivation, while retaining its valuable "wild" characteristics. The fruits of the wild tomato are much more aromatic than modern tomatoes and contain more lycopene - a healthy antioxidant. display

Health value added

The experiment succeeded: within just one generation, the researchers created a new crop. Compared to the starting tomato, this produces ten times as many and three times as much fruit, which is now about the size of a cocktail tomato. In addition, the shape of the new tomato fruits is more oval. This property is popular because the oval fruits burst less quickly in the rain than their round relatives.

In addition, the new tomatoes contain twice as much lycopene as the wild origin, compared to conventional cocktail tomatoes, the content is even more than five times as high. "This is a crucial innovation that can not be achieved with cultivated tomatoes by breeding. Lycopene can help to prevent cancer and cardiovascular disease - so from a health point of view, our tomato probably has added value compared to conventional breeding tomatoes, "says co-author J rg Kudla from the University of M nster.

"Enormous potential"

The new cultivated tomato proves that genetic engineering from wild plants can produce crops with optimal characteristics within a very short time. "Many once lost properties, such as resilience, could normally only be regained through decades of copious backcrossing with the wild plant - if at all, " says Kudla. "With modern genome editing, we can solve this breeding problem."

In the future, not only tomatoes, but also maize, wheat and co. Could be adapted to meet today's needs and eventually become better crops. But that's not all. According to the scientists, this also paves the way for the cultivation of hitherto barely used species.

For example, plants that are very healthy could be turned into entirely new crops by selectively increasing their fruit size or improving other domestication characteristics. "Molecular de novo domestication holds enormous potential, " concludes Kudla. (Nature Biotechnology, 2018; doi: 10.1038 / nbt.4272)

(Westf lische Wilhelms-Universit t M nster, 04.10.2018 - DAL)