Post Brexit, the UK is free to make its own decisions around genetic editing of food crops based on the science. Here, Dermot Martin discusses a research project that seeks to disable a potentially carcenogenic gene in wheat crops and heralds a shift away from EU restrictions that currently treat gene editing the same as genetic modification (GM).
The Government has approved the first trial of wheat which has been genetically modified using the CRISPR technique for a field in Hertfordshire.
A series of experiments over several years will be carried out in Hertfordshire by the agricultural science institute Rothamsted Research (RR). The project’s goal is to produce wheat samples with reduced levels of the amino acid asparagine.
Reducing carcinogenic contamination in baked or toasted bread
When bread is baked or toasted, asparagine is converted into acrylamide – which in certain contexts is regarded as a carcinogenic contaminant which had required close monitoring under EU law.
The food industry has already carried out much work to identify and implement measures to reduce acrylamide levels in food. This includes developing guidance on ways to limit acrylamide formation in a variety of foods and processes. New legislation will require food processors to put in place simple, practical steps to manage acrylamide in their food safety systems. Laboratory and greenhouse studies have already shown CRISPR can be used to create wheat plants that produce much lower levels of asparagine.
RR says that the new five-year project will examine “how the plants fare in the field and whether asparagine concentrations continue to be low in grain produced under field conditions”.
The edited plants will be selectively grown alongside wheat in which asparagine synthesis has been altered using older chemical-induced mutation methods to allow for direct comparison.
Rothamsted scientists claim that cross-pollination with local wild plants or crops is “extremely unlikely to occur” and that “the trial site will be surrounded by a three metre-wide wheat pollen barrier and no cereals or grasses will be allowed to grow within 20 metres of the trial”. The total area for the trial and pollen barrier will be around 1.500 square metres.
Current regulation for gene-edited crops
Under current law, gene-edited crops, in which minor alterations are made using precise techniques like CRISPR are treated the same way under law as transgenic organisms whose genomes include DNA introduced from other species.
The current regulations essentially ban bringing any of these products to market. However, the government is carrying out a consultation programme on the issue which may lead to new legislation allowing farmers to plant gene-edited crops.
“It is essential that we test the wheat in field trials to see how it performs, not only in terms of asparagine concentration but also yield, protein content and other quality and agronomic traits,’ said project leader Nigel Halford via the Rothamsted’s website.
“If it comes through the field trial well it could be made available to wheat breeders. Even so, it would be another five to 10 years before very low asparagine wheat could appear on the market, and that would only be if the regulatory framework were conducive.”
Knocking out the asparagine sythetase gene
During development in the lab, researchers claimed to have knocked out the asparagine synthetase gene, TaASN2.
Asparagine concentrations in the grain of the edited plants were substantially reduced compared with unedited plants, with one line showing a more than 90% reduction, according to project scientist Sarah Raffan speaking to Farmers Weekly recently.
“This new trial will now measure the amount of asparagine in the grain of the same wheat when grown in the field, and assess other aspects of the wheat’s performance, such as yield and protein content,” said Dr Raffan.
Post Brexit freedom to revise regulation
George Eustice, secretary of state for the environment for food and rural affairs (Defra) told a farming conference in Oxford in January that in a post Brexit world, the UK is free to make its own decisions based on the science. He signalled plans to move away from EU restrictions that currently treat gene editing the same as genetic modification (GM).
Unlike GM, gene-edited organisms do not contain DNA from different species, Mr Eustice explained. They only involve changes that could have been made using traditional breeding methods.
Rothamsted scientists hope that the UK Government consultation will lead to new legislation allowing regulated gene-edited food products to be available to consumers.
But affects of contamination risk being mitigated are ambiguous
The affects of acrylamide are ambiguous. Rodents studies have found acrylamide exposure increases the risk for several types of cancer. In the body, acrylamide is converted to glycidamide, which causes potential mutations and damage to DNA. However, a large number of epidemiologic studies, both case control and cohort studies, in humans have found no consistent evidence that dietary acrylamide exposure is associated with the risk of any type of cancer.
One reason for the inconsistent findings may be the difficulty in determining an individuals’ acrylamide intake based on reported diet.
Funding for the trial comes from the Biotechnology and Biological Sciences Research Council is in place for the first year. Additional support is being sought for the subsequent years.
file:///Dietary acrylamide and human cancer/ a systematic review of literature. Nutrition and Cancer 2014%3B66(5)/774-790. Virk-Baker MK, Nagy TR, Barnes S, Groopman J.
Author: Dermot Martin is a freelance science writer