October is Non-GMO Month!

New GMO Alert – Purple Tomato Recently Approved for U.S. Import and Cultivation

Eat two tomatoes and call me in the morning

As new GMO techniques such as CRISPR are making it easier and cheaper to genetically modify plants, researchers are expanding their focus to manipulate different types of crops, those that fall outside of what we have come to identify as likely being GMO, such as corn, soy, cotton, sugar beet, and canola. They are also expanding the types of traits that are being engineered into these plants, with some of those traits being created in hopes of providing some sort of health benefit. One of the most popular plants du jour for this experimentation is the tomato.

The “purple tomato” was recently approved for U.S. import and cultivation by USDA/APHIS, a little over a year after the application was first submitted in July 2021. It was developed by scientists at Norfolk Plant Sciences (Norfolk), which is located at, and is a spinout of, the John Innes Centre in Norwich, U.K. The tomato species Solanum lycopersicum was genetically engineered to have greater levels of anthocyanin, which is thought to have beneficial health effects. The company says about half a cup of purple tomatoes is estimated to contain the same amount of anthocyanin as half a cup of blueberries.

The transgenic tomato was modified using genetic material from the snapdragon (to control anthocyanin levels) and Arabidopsis thaliana (as a flavanol activator). Purple tomatoes aren’t new; there are over two dozen varieties of tomatoes that feature some degree of purple skin, many of them heirloom varieties. What makes this GM purple tomato distinct is that it also features purple flesh.

The purple tomato represents the first GM crop to undergo USDA/APHIS review under the new SECURE rule, which was promulgated in 2020. Thus, in addition to receiving the USDA’s stamp of approval for both import and cultivation, any future versions (i.e., events) of the purple tomato that involve the same species, traits, and mechanisms of action will not be regulated. Norfolk plans to release the tomato for sale in limited markets in 2023.

However, the purple tomato is not the first genetically modified tomato to reach the table. Sanatech Seed (Sanatech) launched the GM Sicilian Rouge GABA tomato in Japan in 2021, after the Japanese government determined that the tomato would not be regulated as a genetically modified product. Sanatech, in conjunction with scientists at the University of Tsukuba, used CRISPR to genetically modify the tomato to have high levels of gamma-aminobutyric acid (GABA), an amino acid thought to help manage hypertension. The tomatoes were first made available to home gardeners as seedlings and were then released for sale directly to consumers in September of last year.

Researchers at the John Innes Centre have also been working to develop GM tomatoes with other traits. It was recently reported that they had created a CRISPR “Vitamin D” tomato, boosting the amount of Vitamin D in the skin and flesh of a tomato to equal that present in two eggs. The tomato leaves were found to also contain high levels of Vitamin D3, leading researchers to speculate that the leaves could serve as a vegan source of Vitamin D3 for supplements. Researchers there are also working to create a tomato that accumulates and expresses L-DOPA, an amino acid that is used to treat Parkinson’s Disease.

In all of these instances, the tomato was likely chosen in part because of its popularity with consumers. It remains to be seen whether or to what extent the increased health benefits purported through the creation of these GM traits are ultimately realized.

That being said, these health benefit traits bring to mind Golden Rice, a crop that had been genetically modified to produce beta-carotene with the goal of addressing Vitamin A deficiency, especially in children with poor nutrition. Since its initial development in the late 1990s (GR1), and subsequent iterative event in the early 2000s (GR2E), Golden Rice has been highly controversial for a wide range of reasons – reasons beyond its GM origins – including cost; yield; and nutrient value, bioavailability, and degradation. At the present time, only one country, the Philippines, is commercially growing Golden Rice, and that process has only recently begun.

In 2018, Golden Rice (GR2E) received the approval of the FDA, but it is interesting to note that in its approval, the FDA stated that the levels of beta-carotene in GR2E rice were too low to warrant a nutrient content claim.

If the purple tomato is sold in the U.S. next year, it will be one of a few GM crops to be sold directly to consumers. Due to lack of consumer acceptance, most GMO crops such as corn and soy are marketed toward farmers. The GMO crops are then used primarily as feed for livestock or are highly processed before being sold directly to consumers.