Imagine if plants could tell us exactly when they're stressed, infected, or being eaten by insects, by lighting up? A new study led by Dr Karen Sarkisyan, Head of the Synthetic Biology group at the MRC Laboratory of Medical Sciences (LMS), has borrowed molecular machinery from mushrooms and inserted it into plants to do just that.
Published in Nature Communications, the scientists engineered plants that could glow in the dark whenever their natural immune systems switch on. The team achieved this by combining two remarkable things plants already have:
Defence hormones, salicylic acid and jasmonic acid, which plants use as internal signals to trigger fighting off different types of threats
A bioluminescence pathway derived from glow-in-the-dark mushrooms, that has been edited into the plants genome to allow them to glow under certain circumstances.
By connecting these two systems, the researchers created plants whose immune responses can be directly visualised as light. When a plant detects danger, the relevant hormone pathway switches on the glow in the dark genes, causing the injured plants to emit a green glow.
What did the team discover?
Using everyday cameras without the need for specialised microscopes or the addition of extra chemicals, the scientists watched plants respond to a variety of challenges: They discovered that wounded plants with tissue damage would light up within just a few hours, as would plants which had been injured by insect bites. Plants which were infected by pathogenic bacteria triggered different glowing patterns, reflecting the type of immune response. The scientists also discovered that during normal plant growth some aspects of the plant were brighter during flowering, matching known hormone activity during reproduction.
These glowing plants provide a vivid window into plant behaviour that usually goes unseen.
Why does this matter?
Plant diseases and pests threaten global food security, and early detection of stress is key to protecting crops. This new technology could help researchers understand how plants respond to real-world environmental conditions in the future, enabling screening of crop varieties for disease resistance,
support sustainable agriculture by reducing reliance on pesticides,
make it easier to study plant health in greenhouses or even in the field.
It also shows how synthetic biology can create simple, low-cost tools that turn invisible molecular processes into something easily observable.
A new way to "listen" to plants
Because the plants produce their own luminescent substrate, they can be imaged over long periods without harming them meaning that for the first time, researchers can watch plant immune responses as they naturally unfold.
The project involved collaborators across the Czech Republic, Russia, the US and the UK. The LMS team contributed synthetic biology expertise from the LMS's Synthetic Biology Group.
"By giving plants the ability to produce their own light in response to immune activation, we can watch defences unfold in real time using nothing more than a standard camera. This opens up experiments that were previously impossible outside specialised imaging facilities," says Karen.
The work was funded by several funders, including the Medical Research Council and Biotechnology and Biological Sciences Research Council through the International Science Partnerships Fund.
