A team led by Russian researchers has accomplished something quite impressive: they have created plants that produce their own light.
The results were shared in the journal Nature Biotechnology on Monday (27). Experts have found that the bioluminescence found in some mushrooms is metabolically similar to the natural processes that occur in plants. Thus, by inserting the DNA of one of these fungi into the vegetables, the team created plants that shine more intensely than the bioluminescent plants that have been created so far.
“Thirty years ago, I helped to create the first luminescent plant using a gene from fireflies,” said Keith Wood, CEO of Light Bio, the company that participated in the project, in a statement. “These new plants can produce a much brighter and more steady glow, which is fully embodied within their genetic code.”
According to the scientists, in contrast to other commonly used forms of bioluminescence, such as fireflies, exclusive chemical reagents are not needed to sustain the bioluminescence created from mushrooms. In addition, plants that contain the fungus’ DNA shine continuously throughout their life cycle, from the point when they were seedlings to maturity.
This biological light can be used by scientists to observe the inner workings of plants. The team found that the location of the luminescence changes as the plants grow, decreasing as the leaves age and increasing where they were damaged.
“In the future, this technology can be used to monitor plant responses to various stresses and changes in the environment, such as drought or wounding by herbivores,” Karen Sarkisyan, CEO of Planta, the startup that led the project, told The Guardian.
The researcher hopes that, in the future, the fungi genes may be associated with specific parts of plants, such as hormones. “You should be able to see the light coming only from the tissues where the hormone is currently active,” exemplified Sarkisyan.
For Professor John Carr, from the University of Cambridge, England, who did not participate in the research, the challenge now is to discover how to make projected bioluminescence responsive to environmental stimuli. “This is essential if the technique will, literally, be able to throw new light on fundamental biological processes,” he told The Guardian.
Besides, the novelty can be used for practical purposes, such as lighting in public places, and aesthetic, mainly for the creation of bright flowers and other ornamental plants. “We really hope to bring this to the market in a few years from now, once we make them a bit brighter, once we make the ornamental plants with this new technology, and once of course they pass all the existing safety regulations,” noted Sarkisyan.
Although mushrooms are not closely related to plants, their light emission is concentrated in an organic molecule that also exists in plants and is responsible for building cell walls. This molecule, called caffeic acid, produces light from a metabolic cycle involving four enzymes.
According to the researchers, two enzymes convert caffeic acid into a luminescent precursor, which is then oxidized by a third to produce a photon. Then, the last enzyme converts the oxidized molecule back into caffeic acid so that the cycle starts over.
In plants, caffeic acid is a component of lignin, which helps provide resistance to cell walls. By connecting light production to the molecule, the glow emitted by plants provides an internal metabolic indicator that can reveal the physiological status of plants and their responses to the environment.
For example, younger parts of the plants tend to shine more brightly, and the flowers are particularly luminous. These flickering patterns, or waves of light, are often visible, revealing active behaviors within the plants that would normally be hidden.
The research authors mainly used tobacco plants in the research because of their simple genetics and rapid growth, but mushroom bioluminescence is largely suitable for plants. According to them, the brightness is viable in periwinkles, petunias and roses, but the team believes that other plant species will respond in the same way in future tests.
According to the authors, “shiny” plants have been studied and developed before based mainly on bacterial genes. However, the new specimens can produce more than 1 billion photons per minute – which makes them apparently 10 times brighter than the one produced using bacteria.
“We tend to overlook plants, we tend to not appreciate how complex or how alive they are. They send a lot of different signals, they integrate and make a lot of developmental decisions, and we don’t really appreciate them,” commented Sarkisyan in an interview with CNN. “Making them glow somehow builds a new relationship with the plants, and you can appreciate much easier how alive they are.”