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Scientists create plants that change colors when toxic chemicals are present

In a fascinating study that seems straight out of science fiction, researchers at UC Riverside have engineered a house plant that signals contamination by turning a vivid beet red in the presence of certain toxic chemicals.

This innovation, led by a team of scientists seeking a more interactive form of environmental monitoring, could revolutionize how we detect unsafe substances in our surroundings.

Sentinel plants and chemicals

The project was spearheaded by associate professor of chemical and environmental engineering Ian Wheeldon, and involved a delicate balancing act. The team needed to create a plant capable of identifying specific environmental toxins without hindering its natural growth processes or survival mechanisms.

“Our goal was to integrate a responsive sensor without disrupting the plant’s inherent functions,” Wheeldon explained. “Earlier approaches often interfered with vital processes like phototropism or water conservation during stress. Our technique maintains these essential functions intact.”

Mechanism behind the response

Central to this feat was manipulating a biological pathway involving abscisic acid (ABA), a plant hormone that adapts plant behavior to stressful scenarios such as drought. Under such conditions, plants synthesize ABA. This acid then binds to specific receptor proteins, initiating a survival response from the plants — closing their stomata to prevent water loss, for instance.

The breakthrough came when they discovered that these ABA receptors could be re-engineered to recognize other chemicals beyond ABA. For demonstration purposes, they chose azinphos-ethyl, a pesticide known for its toxicity and consequent ban in multiple jurisdictions.

“Reprogramming the ABA receptors was crucial. We essentially taught the plant to respond to a contaminant with a visual cue,” said Sean Cutler, UCR professor of plant cell biology. “Imagine a field of plants suddenly turning red, flagging the presence of a harmful substance. The implications for real-time environmental monitoring are profound.”

Plants can do more than identify chemicals

The team’s vision extends far beyond pesticides. They aim to create living sensors capable of detecting a spectrum of substances. These would include pharmaceuticals that have found their way into water supplies.

“Our current success is just the beginning. We’re exploring the plant’s potential to detect an array of chemicals,” noted Cutler. “Concerns are growing over pollutants like residual medications in our water. Our research is a leap toward addressing these issues effectively.”

However, the technology is still in its infancy and not without its challenges. The ambition to engineer plants that can detect multiple substances simultaneously, for instance, has yet to be realized. The team did manage this feat in yeast, demonstrating its potential. However, replicating this in plants requires more complex biotechnological advancements.

Regulatory hurdles and future applications

Despite its promise, this botanical innovation won’t appear in commercial applications anytime soon. Regulatory approval for such genetically engineered organisms is a lengthy and complex process, ensuring they are safe for larger ecosystems.

Moreover, practical issues need addressing before these sentinel plants can be part of everyday environmental health or defense mechanisms. These include understanding the plants’ responses under different conditions, and ensuring they can be effectively deployed in varied environments.

While it may be years before these red-alert plants are part of our home gardens or community spaces, the study marks a significant step forward in the realm of environmental science and bioengineering.

With further research and refinement, sentinel plants offer a visually striking, immediate method for identifying risks in our surroundings. They will soon contribute significantly to public health and safety initiatives worldwide.

As science continues to bridge the gap between the natural and technological worlds, it’s not hard to imagine a future where our own gardens contribute to a healthier, safer planet for all.

The full study was published in the journal Nature Chemical Biology.

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