Gene editing enables tomatoes to make ‘sunshine vitamin’

Scientists in the UK have successfully created tomatoes that make large amounts of vitamin D in their leaves and fruit using pioneering gene editing technology.

The researchers say the international project, led by the John Innes Centre in Norwich, could address a global health problem, with more than 1bn people estimated to be deficient in the “sunshine vitamin”.

Details were published in the journal Nature Plants on Monday, two days before the government is due to introduce its genetic technologies bill, which will enable the UK to develop and commercialise gene-edited crops faster than it had been able to before Brexit as a member of the EU.

Gideon Henderson, chief scientist at the Department for Environment, Food and Rural Affairs, called the project “a fortuitously timed and very nice example” of the sort of gene editing development that would be accelerated under the proposed legislation.

Ahead of the bill becoming law, the government has relaxed UK regulations for field trials of gene-edited crops, which will enable the John Innes Centre team to grow vitamin D tomatoes outdoors in Norfolk this summer, said Cathie Martin, the project’s senior researcher.

It would take at least two years for the centre’s scientific partners in Italy to get permission for a comparable field trial there, she added.

The researchers used Crispr, the most popular gene editing technology, to make a tiny change in the tomato’s DNA. This greatly increased concentrations in both leaves and fruit of a molecule called provitamin D3. The molecule is then converted through exposure to ultraviolet light or sunshine into D3, the vitamin’s most beneficial form in humans.

Tomatoes grown under ultraviolet illumination in John Innes Centre greenhouses contained enough vitamin D3 for two medium-sized fruit to satisfy an average adult’s daily requirements, said Jie Li, the study’s lead author.

The plants grew as well as the same tomato varieties that had not been gene edited, and their fruit were indistinguishable in appearance and flavour.

The field trial will show whether gene-edited tomatoes ripened outdoors in English sunshine will be similarly enriched. If not, vitamin D concentrations could be increased by drying them in the sun — or growing them in Italy.

“Forty per cent of Europeans have vitamin D insufficiency and so do 1bn people worldwide,” said Martin. “We are not only addressing a huge health problem but are helping producers, because tomato leaves which currently go to waste could be used to make supplements from the gene-edited lines.”

Martin said the technology could be particularly useful for vegans because animals and fish are the main sources of vitamin D3, including vitamin D supplement pills and capsules.

The next steps in the project will be to assess the nutritional benefits of the gene-edited tomatoes and make sure that their vitamin D can be successfully absorbed, while technology is developed to extract the vitamin as efficiently as possible from waste leaves and stalks.

John Innes Centre, a publicly-funded research laboratory, will make its gene editing technology freely available to any commercial breeders, said Martin, though they might need to negotiate licensing agreements with Crispr patent holders.