Researchers have identified the bitter substances in Belgian endives and chicory. Using the gene-editing technique CRISPR/Cas9, they have also succeeded in eliminating them. The result is a less bitter vegetable that may be more appetizing to children and adults alike. The catch? Outdated EU gene editing laws present a major roadblock for any company looking to actually produce the vegetables in Europe.
By Amy LeBlanc
Common chicory is a plant which has been cultivated as a food crop for millennia. Different variations of the plant species are used to produce chicory roots, radicchio, and Belgian endives (also known as witlof). Chicory and its derivations have a characteristically bitter taste, an aspect which not everyone loves, with children in particular often turning their noses up at bitter leaves. The popularity of these plants has been dwindling, and although the Belgian endive remains in the top ten most eaten vegetables in the country, the decreased demand amongst young people has led to less of the crops being grown.
In addition to its culinary uses, chicory is also cultivated for the production of inulin, a type of dietary fiber commonly used in the food industry as a healthy, gluten-free flour. The food industry would be very interested in a less bitter chicory variety, as the roots could then be processed into flour immediately after drying and grinding, without first having to extract and purify the inulin.
Clearly, there is still potential in chicory and Belgian endives, especially if we can make them less bitter to meet the changing demand of consumers and industry. Rising to the challenge, bio-engineer Charlotte De Bruyn (of UGent/VIB and ILVO) began her doctoral research project by searching for the genes responsible for the bitter taste of Belgian endives and chicory. She was assisted by VIB researcher Alain Goossens, who specialized in taste-influencing substances, and ILVO researcher Katrijn Van Laere, an expert in classic and advanced plant breeding techniques.
CRISPR chicory
Working with the chicory parent plant Cichorium intybus, Charlotte De Bruyn was able to identify four genes responsible for the bitter taste of the plant, one of which was previously unknown. De Bruyn then used the CRISPR/Cas9 gene editing technique to switch off the genes that control the production of those substances (called guaianolide sesquiterpene lactones) in a few chicory cells.
Read this article to find out more about CRISPR/Cas9, which won the Nobel Prize in Chemistry in 2020!
The cells were grown into full-fledged plants in a lab greenhouse of the Institute for Agricultural, Fisheries and Food Research (ILVO), where De Bruyn could then determine that the experiment has been a success: though the genes are still present in the plants, they are no longer expressed, and the modified chicory plants now hardly produced any bitter substances.
Although the sweeter taste of the ‘crisp chicory’ has yet to be confirmed with a tasting round, the success of the gene editing in reducing the concentration of bitter molecules has led to excitement all around. De Bruyn expects the first crop of leaves from the seedlings in a year’s time.
Europe: outdated laws result in bitterness
Unfortunately, while people in the rest of the world may soon be eating sweeter endives, European consumers will be gnawing on a bitter crop for a while yet. In 2018, the European Court of Justice ruled that CRISPR/Cas9 modified plants fall under the same strict legislation as genetically modified organisms (GMOs) produced with older gene editing techniques, making it almost impossible to market CRISPR crops in the EU. This legislation was drafted before the more modern and precise CRISPR technology even existed, and many have lamented the outdated laws.
While the European Commission is dragging its feet, local agricultural innovation is suffering. AgTech experts are moving to greener pastures, where modern technologies like CRISPR are not only allowed but actively encouraged. Certain types of genetically modified crops – such as GM maize and soybean – are widely grown in other parts of the world, but not in Europe (though the continent still imports these crops from elsewhere).
Read this article to find out why everyone needs to be a part of the CRISPR conversation!
Gene editing is increasingly being viewed as a potential solution for many global food security issues. By precisely editing the genes of crops, we can produce plants that have increased crop yields, decreased resource requirements, lower need for pesticides, and higher tolerance to the effects climate change. Public opinion has also shifted more in favor of gene edited foods, with the main hurdle now being primarily political.
Taking the long way around
Hampered by the EU restrictions, researchers may nevertheless be able to achieve sweet chicory and endives through much slower conventional breeding techniques. Now that the bitter genes have been identified, existing varieties can be searched for natural gene mutations that also lead to a lower production of the bitter substances. By crossing two varieties that already have some of those mutations, researchers may be able to get a get a ‘natural’ equivalent of the CRISPR chicory, with a bit of luck.
Classic breeding like this has been used to similar effect in the past. In the 1990s, after the substances responsible for the bitterness in Brussels sprouts were identified, Dutch scientists painstakingly crossed different sprout varieties in order to achieve a less bitter vegetable. These sweeter sprouts are now the most common variety sold in our supermarkets, and probably the reason you don’t share your parent’s aversion to the greens. But although the sprout story shows that it’s possible, the fact that the sweeter chicory has already been created using CRISPR begs the question: having already achieved our goal, why would we now take the long way around to achieve the same result?
