Gene-edited tomatoes could be a new source of vitamin D: Study
Vitamin D is made in our bodies after the skin is exposed to UVB rays, but the main source is food. This new bio-fortified crop could help millions of people suffering from vitamin D deficiency, a growing problem linked to a higher risk of cancer, dementia and many leading causes of death. . Studies have also shown that vitamin D deficiency is associated with increased severity of infections caused by Covid-19.
Tomatoes naturally contain one of the building blocks of vitamin D3, known as provitamin D3 or 7-dehydrocholesterol (7-DHC),
in their leaves to very low levels. Provitamin D3 does not normally accumulate in ripe tomatoes.
Researchers in Professor Cathie Martin’s group at the John Innes Center used CRISPR-Cas9 gene editing to modify the genetic code of tomato plants to provide vitamin D3 that accumulates in tomato fruit. The leaves of the modified plants contain up to 600 ug of provitamin D3 per gram of dry weight.
The recommended daily amount of vitamin d is 10 ug for adults.
When growing tomatoes, leaves are often waste, but these
Modified plants can be used to produce vegan-friendly vitamin D3 supplements or to add nutrients to foods.
Professor Cathie Martin, corresponding author of the study appearing in Nature, said: “We have demonstrated that you can biologically supplement tomatoes with provitamin D3 using gene editing, which can This means that tomatoes can be developed as a sustainable plant-based source of vitamin D3. Tree.
“Forty percent of Europeans are vitamin D deficient and so are a billion people worldwide. We are not only solving a major health problem, but we are helping producers, because tomato leaves currently being wasted, could be used to make supplements from the gene-editing lineage.”
Previous research investigated the biochemical pathway of how 7-DHC is used in fruit to make molecules and found that a specific enzyme Sl7-DR2 is responsible for converting this chemical into other molecules. other molecules.
To take advantage of this, the researchers used CRISPR-Cas 9 to turn off this Sl7-DR2 enzyme in tomatoes so that 7DHC accumulates in the tomato fruit.
They measured the amount of 7-DHC present in the leaves and fruits of these modified tomato plants and found that there was a significant increase in 7-DHC levels in both the leaves and fruit of the modified plants.
7-DHC accumulates in both the flesh and skin of tomatoes.
The researchers then tested whether 7-DHC in the modified plants could be converted to vitamin D3 by shining UVB rays on the leaves and sliced fruit for 1 hour. They found it worked and worked well.
After treatment with UVB light to turn 7-DHC into Vitamin D3,
One tomato contains the same amount of vitamin D as two medium eggs or 28g of tuna
– both are good sources of vitamin D.
Research says that vitamin D in ripe fruit can be further increased by prolonged exposure to UVB rays, for example during sun exposure.
Inhibition of enzymes in tomatoes did not affect the growth, development or yield of tomato plants. Other closely related plants such as eggplant, potato and pepper have the same biochemical pathway, so the method can be applied to these vegetables.
Earlier this month, the UK Government announced a formal review to look at whether foods and drinks should be fortified with vitamin D to tackle health inequalities.
Most foods are low in vitamin D, and plants are generally very poor sources. Vitamin D3 is the most biologically valuable form of vitamin D and is made in the body when the skin is exposed to sunlight.
In winter and in higher latitudes, people need to get vitamin D from their diet or supplements because sunlight isn’t strong enough for the body to produce vitamin D naturally.
The study’s first author, Dr Jie Li, said: “The Covid-19 pandemic has helped highlight the problem of vitamin D deficiency and its impact on our immune function and general health. The vitamin D-enriched tomatoes we’ve produced provide much-needed plant-based sources of the sunshine vitamin which is great news for those on a plant-based, vegan diet or vegan and for more and more people all over the world suffering from vitamin D deficiency.”
‘Bio-fortified tomatoes provide a new route to getting enough vitamin D’ appears in Natural plants.