In collaboration with researchers from the University of Hong Kong (HKU), the team succeeded in isolating a specific plant chemical pathway to enhance phytosterol content by 94%, squalene (210%), provitamin A (169%) and lycopene (111%).
But with an improvement of vitamin E (α-tocopherol) content of 494%, lead study author professor Chye Mee-len said “increasing health-promoting components in crops is an important research area on the use of plant biotechnology for a sustainable future”.
“The accumulation of the healthy components in food crops would provide added-value to fruits and vegetables in the human diet, as well as enrich feed for livestock and aquaculture.”
Currently there are no genetically modified tomatoes available commercially. In 2014, Norfolk Plant Sciences attempted to commercialise its produce, a genetically modified purple-fleshed tomato that contained high levels of anti-oxidants and anthocyanins.
Teaming up with Canadian-based New Energy Farms, the venture sought to grow a crop of blue tomatoes for use in clinical trials required to obtain regulatory approval.
In March of this year, Sainsbury Laboratory in Norwich, UK detailed a gene-editing technique (CRISPR/Cas9) that made tomatoes resistant to a potent fungal pathogen.
Led by Chye, the Wilson and Amelia Wong professor in plant biotechnology at HKU, alongside colleagues from the Institut de Biologie Moléculaire des Plantes in Strasbourg, France, the trial involved inserting a gene from an Indian mustard plant into a tomato plant.
The team found that as well as the boost vitamin E, provitamin A and lycopene compared to the control group, the increase resulted in a darker colour of the carotenoids extracted from the modified tomatoes.
“Extracts with enriched phytosterols, vitamin E and carotenoids can be used in the production of anti-ageing cream and sun-care lotion,” added Dr Wang Mingfu
“These compounds show excellent anti-inflammatory and antioxidant activity.”
GM tomatoes in the EU
While tomatoes have been regularly used as a model organism to study the effect of climate in fruit ripening, its commercial history is a chequered one.
The Flavr Savr breed of tomato became the first commercially available genetically modified food engineered to have a longer shelf life. Launched in 1994, the tomato did not appeal to consumers and were withdrawn in 1997.
Currently Europe has yet to come to a decision regarding certain technologies implemented to create GMO foods.
In 2007, the European Union set up working groups to clarify how newer cis- and intragenic techniques fit into its existing prohibition of most genetically modified foods.
These working groups published a report in 2012, but not all recommendations were made available to the public.
The commission were scheduled to provide an update in 2015 but pushed back the release of its findings.
In 2016, the French Council of State asked the European Court of Justice (ECJ) to rule whether or not new GMO techniques, including CRISPR-Cas fell under EU GMO law.
The council also asked the ECJ if these ‘new plant breeding techniques’ were to become exempt from EU GMO rules, would this endanger the precautionary principle.
So far, no crops derived from these breeding techniques have yet received EU authorisation because of the uncertain legal situation.
One of the issues EU regulation is wrestling with is whether CRISPR is a definitive GMO technique.
There is the suggestion that CRISPR, when used to change a number of nucleotides to knockin or knockout various endogenous gene pathways in a crop organism, the plant is not considered GMO.
Conversely, an organism is considered GMO if CRISPR is used to insert an entire exogenous gene sequence into an organism.
According to the French Council of State, the ruling is expected around April 2018.
Source: Plant Biotechnology Journal
Published online ahead of print: DOI: 10.1111/pbi.12828
“Improved fruit α-tocopherol, carotenoid, squalene and phytosterol contents through manipulation of Brassica juncea 3-HYDROXY-3-METHYLGLUTARYL-COA SYNTHASE1 in transgenic tomato.”
Authors: Pan Liao, Xinjian Chen, Mingfu Wang, Thomas J. Bach, Mee-Len Chye