Gene-edited tomatoes could be a new source of vitamin D
Dr Jie Li examines vitamin D enriched tomatoes. Credit: Phil Robinson

Tomatoes could be a simple and sustainable innovation to address a global health problem.

Researchers used gene editing to turn off a specific molecule in the plant's genome which increased provitamin D3 in both the fruit and leaves of tomato plants. Exposure to UVB light converted it to vitamins D and D3.

Food is the main source of vitamins D and E in our bodies. A new crop that is biofortified could help millions of people who are deficient in the sunshine. Studies have shown that insufficiency of vitamins D and D2 is linked to increased severity of infections.

Tomatoes have provitamin D3 in their leaves at very low levels. Provitamin D3 doesn't accumulate in ripe tomato fruits.

The group of researchers at the John Innes Centre used gene editing to make changes to the genetic code of tomato plants so that provitamin D3 accumulates in the fruit. The leaves of the edited plants had up to 600 ug of provitamin D3 per gram of dry weight. The recommended daily intake is 10ug for adults.

The edited plants could be used for the manufacture of vegan-friendly vitamins, or for food fortification.

We have shown that you can biofortify tomatoes with provitamin D3 using gene editing, which means tomatoes could be developed as a plant-based, sustainable source of vitamins D3 and D3.

One billion people around the world have insufficient levels of vitamin D. We are 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.

The biochemical pathway of how 7-DHC is used in the fruit has been studied and it has been found that a particularidase is responsible for converting this into other molecule.

To take advantage of this, the researchers switched off the Sl7-DR2 in tomato so that the 7DHC could accumulate in the fruit.

They measured how much 7-DHC there was in the leaves and fruit of the edited tomato plants and found that there was a substantial increase in levels.

The 7-DHC can be seen in the flesh and peel of the tomatoes.

The researchers tested whether the 7-DHC in the edited plants could be converted to vitamins D3 and D3a by shining UVB light on leaves and fruit for an hour. They found that it was very effective.

One tomato contained the equivalent levels of vitamins D and D3 as two medium sized eggs or 28g tuna, which are both recommended sources of vitamins D, after treatment with UVB light.

The study says that exposure to the sun's rays could increase the amount of vitamins D and UVB in ripe fruit.

The growth, development and yield of the tomato plants were unaffected by the blocking of the enzyme. The method could be applied to other vegetable crops that have the same pathway.

The UK Government has announced a review to examine whether food and drink should be fortified with vitamins D and E.

Plants are generally poor sources of vitamins D and E. When the skin is exposed to sunlight, the body makes the most bioavailable form of vitamins D and D3. In winter and higher latitudes the sun is not strong enough for the body to produce it naturally, so people need to get their vitamins from their diet or supplements.

Dr. Jie Li, the first author of the study, said that the COVID-19 pandemic helped to highlight the issue ofvitamin D insufficiency and its impact on our immune function and general health. The provitamin D enriched tomatoes we have produced offer a plant-based source of sunshine vitamins. It's great news for people who want to adopt a plant-rich, vegetarian or vegan diet, and it's also great news for people who are suffering from the problem of insufficiency ofvitamin D.

More information: Cathie Martin et al, Biofortified tomatoes provide a new route to vitamin D sufficiency, Nature Plants (2022). DOI: 10.1038/s41477-022-01154-6. Journal information: Nature Plants Citation: Gene-edited tomatoes could be a new source of vitamin D (2022, May 23) retrieved 23 May 2022 from This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.