CRISPR-Cas9 technology has been used to determine that increasing glucosinolate levels in crops can improve nutrition
When United Kingdom Prime Minister Boris Johnson came to power in July 2019 during the country’s Brexit transition to separate from the European Union, he pledged to sidestep Europe’s grip on curtailing development of genetically modified and gene-edited foods.
Since then, field trials of gene-edited brassica crops conducted by scientists at the John Innes Centre in Norwich have shown immense potential.
The trials took place just as the U.K. government was considering whether to allow gene-editing for food production. More recently, reports have indicated that the European Commission has launched its own review of EU rules on GMOs with the possibility of lightening their tight restrictions.
With new gene-editing methods, a narrow part of an organism’s DNA is cut or edited. Unlike with conventional GM techniques, there is no DNA transfer from one organism into another.
“Modern technologies such as gene editing by CRISPR provide opportunities to nutritionally fortify foods and safely adapt crops to new environments, addressing the serious challenge that the climate crisis is posing to global food production,” said professor Lars Ostergaard, group leader at the John Innes Centre in Norwich, in a news release.
The study focused on glucosinolates (GSLs), sulfur-containing compounds that produce the distinctive flavour in cruciferous vegetables like broccoli, cabbage and kale. The researchers knew from previous laboratory work that the process of glucosinolate biosynthesis is regulated by the gene MYB28, but they needed to test this genetic regulator in a field environment.
They conducted a proof-of-concept study in 2019 in which the CRISPR-Cas9 technology was used to remove the MYB28 gene in Brassica oleracea. Uncultivated, the plant is known as wild cabbage, but its cultivars include cabbage, broccoli, cauliflower, kale, brussel sprouts, collard greens, and kohlrabi.
“The Brassica oleracea species exists in a vast number of different varieties and the one we use has a plant architecture similar to rapeseed,” said Ostergaard.
The plants were grown in a cage and the four-week-old seedlings were planted in April. A sampling of leaf material was done in May. In June, the plants were uprooted before flowering. All sample material from individual plants was kept separate and isolated in sealed containers before being frozen and prepared for analysis.
The field trial was carried out for only one year.
The results confirmed for the first time that the MYB28 gene regulates glucosinolate levels in the field similar to results seen in model plants grown in a greenhouse. Therefore, improving nutrition would mean increasing GSL levels.
“To improve the nutritional value of broccoli, we would take an approach that increases GSL levels by increasing the expression of MYB28,” Ostergaard said.
Genetic manipulation of food crops, by GM methods or by genetic editing, remains under debate in the U.K.
Ostergaard said significant skepticism still exists, but he feels the public is becoming more receptive.
He said that, in fact, there was a CRISPR field trial in 2018 conducted by Rothamsted Research Institute in which genetically edited camelina seeds were planted and studied for improvements in omega-3 fatty acids and to improve the researchers’ understanding of lipid metabolism.
“Both trials have shown the power of transferring the knowledge that we have obtained through fundamental research for the improvement of crops,” he said. “I am convinced that long-term sustainable crop performance combined with climate-friendly agricultural systems can only be achieved through the understanding of fundamental biological processes. The CRISPR technology allows us to immediately implement this understanding.”
Ostergaard is sure that with a government decision to no longer classify gene-editing as genetic manipulation, plant-breeding companies will become increasingly active in taking advantage of this technology.