Researchers use CRISPR to create new antioxidant-rich tomato

Researchers from Brazil, the United States, and Germany have created a new tomato crop from a wild plant using CRISPR-Cas9. Starting with a “wild tomato” they have, at the same time, introduced a variety of crop features without losing the valuable genetic properties of the wild plant. The results have been published in Nature Biotechnology.

“This new method allows us to start from scratch and begin a new domestication process all over again,” said biologist Jörg Kudla from the University of Münster, whose team is involved in the study. “In doing so, we can use all the knowledge on plant genetics and plant domestication that researchers have accumulated over the past decades. We can preserve the genetic potential and the particularly valuable properties of wild plants and, at the same time, produce the desired features of modern crops in a very short time.” Altogether, the researchers spent about three years working on their studies.

The researchers chose Solanum pimpinellifolium as the parent plant species—a wild tomato relative from South America and the progenitor of the modern cultivated tomato. The wild plant’s fruits are only the size of peas and the yield is low—two properties which make it unsuitable as a crop. On the other hand, the fruit is more aromatic than modern tomatoes, which have lost some of their taste due to breeding. Moreover, the wild fruit contains more lycopene, an antioxidant.

The researchers modified the wild plant by using CRISPR-Cas9 in such a way that the offspring plants bore small genetic modifications in six genes. These decisive genes had already been recognized by researchers over the past few years and are seen as the genetic key to features in the domesticated tomato. Specifically, the researchers produced the following modifications in comparison with the wild tomato: the fruit is three times larger than that of the wild tomato, which corresponds to the size of a cherry tomato; there is 10 times the number of fruits; and the shape is more oval than the round wild fruit. The plants also have a more compact growth.

Another important new property is that the lycopene content in the new breed of tomato is more than twice as high as in the wild parent—and no less than five times higher than in conventional cherry tomatoes. So far breeders have tried in vain to increase the lycopene content in cultivated tomatoes. In cases where they were successful, it was at the expense of the beta-carotene content, which also protects cells and is therefore a valuable ingredient.

Press release