Scientists have created a genetically modified citrus that, surprisingly, turns limes purple. With the help of anthocyanins, pigments that give plants their red, blue or purple coloration, researchers have developed a lime which appears to be ruby or purple at its center.
In this latest study, the researchers genetically engineered a lime that contains anthocyanins. The lime itself was a "Mexican lime," which does not produce anthocyanin naturally. In the end, the scientists produced plants that expressed either a myb-related anthocyanin biosynthesis regulatory gene cloned from the red grape "Ruby Seedless" or from the "Moro" blood orange.
The newly engineered plant resulted in anthocyanin pigmentation in the leaves, stems, flowers and fruit. There was also increased pigmentation in the outer layers of stem tissue in the lime overexpressing the VvmybA1 gene from the red grape. Surprisingly, the researchers found that there were lower anthocyanin levels in plants that overexpressed Ruby, from the blood orange.
This isn't all that researchers found when creating the newly engineered plants. When the plants were young, there were relatively high pigmentation levels in the young leaves. But as the plants and leaves matured, the pigment intensity levels decreased.
With that said, the flower colors in the plants seemed to range from pink to fuchsia. Likewise, the pulp color of the limes also ranged. While some of the lime pulp was a deep purple or maroon in color, others took one a pinker hue.
"Our report outlines the successful production of transgenic 'Mexican' lime plants, resulting in the production of anthocyanins in a citrus cultivar that does not produce anthocyanin naturally," the authors of the new paper describing the citrus wrote. "These plants exhibited unique leaf pigmentation, flower coloration, and pulp enhanced by anthocyanin overproduction."
The limes don't just look pretty; they also have potential health benefits, according to the researchers. With that said, they will have to undergo rigorous testing before being released to markets.
The newly developed limes could be used in many different ways. For example, they could be used as ornamental plants due to their coloration and pigmentation. After more testing, they could also be used in fruit markets due to their beautifully-colored fruit. The researchers are also hoping that their work, published in the Journal of the American Society for Horticultural Science, could eventually lead to the creation of modified orange or grapefruit cultivars, as well.
