by Scientists have genetically engineered a special ‘golden lettuce’ that provides significantly higher amounts of vitamin A, a nutrient necessary for our immune function, vision and growth and development.
Not only could the product itself provide a crucial nutrient to consumers, the same approach could also be used to give other vegetables a health boost in the future.
After increasing the compound fivefold in the tobacco family Nicotiana benthamianathe team led by scientists from the Polytechnic University of Valencia (UPV) in Spain has modified the genetic composition of lettuce (Lactuca sativa) to increase beta-carotene levels; a red-orange colored compound that is converted into vitamin A in our body.
Usually stored in the small green ‘solar panels’ that power photosynthesis known as chloroplasts, increasing the plant’s beta-carotene supply, would have been disruptive. TTo avoid disrupting the natural photosynthetic processes that lettuce needs to live and grow, the researchers had to think outside the box.
“Leaves need carotenoids, such as beta-carotene in the photosynthetic complexes of chloroplasts, to function properly,” says UPV molecular biologist Manuel Rodríguez Concepción. “If too much or too little beta-carotene is produced in the chloroplasts, they stop functioning and the leaves eventually die.”
“Our work successfully produced and accumulated beta-carotene in cellular compartments where it is not normally found by combining biotechnological techniques and treatments with high light intensity.”
Some of the extra beta-carotene was stored in the cytosol, the liquid part of the leaf cells. More of the compound was produced by converting some chloroplasts into chromoplasts (or pigment pits) – via the introduction of the gene for the bacterial enzyme crtB – which can store even more beta-carotene.
In addition to the genetic modifications, the plants were also subjected to high-intensity light treatments, which led to more fat storage units, known as plastoglobules, in the lettuce.
“Stimulating the formation and development of plastoglobules with molecular techniques and intensive light treatments not only increases the accumulation of beta-carotene, but also its bioaccessibility,” says molecular biologist Luca Morelli from UPV.
Improving the bioaccessibility of lettuce’s supply of beta-carotene increases its availability in the intestines, where it is converted into vitamin A. All this extra beta-carotene – which is found in abundance in carrots and pumpkins – makes the lettuce yellow, hence the name the researchers gave it.
A 2023 study found that vitamin A deficiency affects hundreds of millions of developing bodies around the world. Finding new ways to give more people’s diets a much-needed upgrade is critical to limiting the impact of poor nutrition.
“Micronutrient deficiency, also known as hidden hunger, is still a major problem in many countries,” the researchers write in their published paper.
“Specifically, vitamin A deficiency causes xerophthalmia and can lead to other health problems and even death, affecting children from malnourished populations around the world.”
The research has been published in the Plant diary.
