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Bomb-sniffing plants to the rescue

Bomb-sniffing plants could make airport security a whole lot greener – at least until a bomb-packing terrorist walks by and causes the leaves to turn white, researchers report in the journal PLoS ONE.

The plants are being grown by a research team headed by June Medford, a biologist at Colorado State University in Fort Collins, with funding from the Depart of Defense and a host of other agencies.

The trick involves using DNA to rewire the plants' protein-based signaling process, so that the leaves change color when certain chemicals or environmental pollutants are detected. Plants usually rely on the system to release toxins that ward off insects looking for a leafy meal.

"Plants can't run or hide from threats, so they've developed sophisticated systems to detect and respond to their environment. We've taught plants how to detect things we're interested in and respond in a way anyone can see to tell us there's something nasty around," Medford explained in a news release.

To get there, Medford's colleagues used a computer program to redesign receptors in plant cells to recognize a specific pollutant or explosive. Then she and colleagues at her lab modified the redesigned receptors to function in the cell walls of the plants.

So far, the researchers have grown Arabidopsis and tobacco plants in the lab that respond to an explosive by "de-greening" within a few hours. Next-generation greenery should make the change in color in a matter of minutes.

The plants will be ready for prime time in about three to four years, Medford told's Danger Room. Potential applications include airport security as well as at public gathering places such as football stadiums. They could even find use around a home — turning white, for example, when radon is detected.

What's more, these rewired proteins can live in any kind of plant, giving green thumbs with an appreciation for biotech a new world of choices when considering what to grow next.

More stories on bomb sniffing and plant technology:

TIn addition to Medford, co-authors of the PLoS ONE paper, "Programmable Ligand Detection System in Plants Through a Synthetic Signal Transduction Pathway," include Mauricio Antunes, Kevin Morey, Jeff Smith, Kirk Albrecht, Tessa Bowen, Jeffrey Zdunek, Jared Troupe, Matthew Cuneo, Colleen Webb and Homme Hellinga.

Project funding is from Defense Advanced Research Projects Agency, or DARPA, the Office of Naval Research, the Bioscience Discovery Evaluation Grant Program through the Colorado Office of Economic Development and International Trade, the National Science Foundation, the Department of Homeland Security Science and Technology Directorate and Gitam Technologies.

John Roach is a contributing writer for Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following's science editor, Alan Boyle, on Twitter (@b0yle).