Brighter than ever: genetic engineers present designer plants that continuously generate radiation that is visible to the naked eye without additional aids. The transmission of a genetic luminescence program from luminous mushrooms ensures the innovative luminosity. The concept could serve plant research, but could also make radiant ornamental plants possible, say the scientists.
It is an old hat, you might think: genetically modified plants or tissues with special lighting effects have been around for a long time. In many cases, however, the shimmer is not based on an independent luminosity (luminescence), but on what is known as biofluorescence. Thereby, substances are stimulated to glow by irradiation with special light frequencies. However, there was also real luminescence in plants: genes of the firefly were transmitted or light programs of certain types of bacteria in plant cells were activated. But the effects remained weak or additional treatments were needed to create the light. Luminous plants, such as those that illuminate the forest in the science fiction film “Avatar”, were previously not possible.
Mushroom luminosity transmitted
But the international team of researchers led by Karen Sarkisyan from the London Institute of Medical Sciences is turning your imagination into reality. As they report, their plants are significantly lighter than all previous genetic engineering plants with luminescence effects. This is made possible by the transfer of the genetic basis of a lighting system that comes from luminescent mushrooms. Only in recent years has it been possible to uncover the genetic concept of this light generation. It is much better suited for use in plants than the system of fireflies or luminous bacteria, the scientists say.
As they explain, the light emission in the new concept is based on an organic molecule that is also naturally found in all plants: the so-called caffeic acid plays an important role in building up cell walls. In the mushrooms’ luminescence process, this substance produces light through a metabolic cycle, in which four other substances are involved, the researchers report: two enzymes convert the caffeic acid into a luminescent precursor, which is then oxidized by a third enzyme to produce a photon . The last enzyme then converts the oxidized molecule back to caffeic acid so that the cycle can remain active continuously.
As part of their study, the scientists have now equipped tobacco plants with the necessary genetic components for the fungal bioluminescence system. Because of their easy handling, they are often used as model plants in genetics. In principle, the genetic program can be introduced into the genome of many plant species, the scientists say. With the concept of tobacco, they were able to provide a clearly visible glow in the dark: the greenish light from leaves, stems, roots and flowers, which they present in the course of their study, was recorded with ordinary cameras and smartphones. From the time of germination, these tissues continuously generate light without impairing the vitality of the plants, the scientists report.
Scientific and commercial potential
Due to the clear visibility, they are now able to develop ornamental plants that glow in the dark. One company is apparently already implementing this idea. Radiant genetic engineering roses and other bright ornamental plants are unlikely to generate general enthusiasm. However, as the researchers emphasize, there is also scientific potential in the concept: it could literally bring light into the inner life of plants.
As the researchers explain, the radiation activity of plants can provide an indication of metabolic processes, for example, since the generation of light is linked to the caffeic acid that is important for growth. The scientists report that it is often possible to detect changing patterns or waves in the generation of light, which reveal the processes within the plants. Accordingly, the lighting effects could provide important insights into the physiological conditions of plants and their reactions to the environment. So it will be interesting to see how the concept will develop scientifically or commercially.
Video: Insight into the growth of the glowing plants. Credit: Planta
Source: London Institute of Medical Sciences, professional article: Nature Biotechnology, doi: 10.1038 / s41587-020-0500-9