How tobacco plants could be the next bomb detectors

"It sounds like the setting from the latest science fiction film: an airport equipped with a forest of bomb-detecting plants that can sniff out potential terrorists. But according to June Medford and her team from Colorado State University, their rewired plants could turn this scenario into reality.

In the new study, published online in PLoS One, the team engineered tobacco plants and mouse-ear cress (Arabidopsis thaliana) to turn yellow when they detect minute concentrations of explosives in the air. Using a computer program, they redesigned receptor proteins to respond to TNT. Consequently, when the plants are exposed to vapours from the explosive, TNT molecules bind to the receptors on the plant tissues and the leaves lose their green hue.

Currently, the plants can change colour within hours - and are 100 times more sensitive to chemical signals than a dog's nostrils - but they will need to respond within seconds or minutes to be truly useful as green watchdogs. Funding by the Department of Defense and Homeland Security will help the Colorado team to take this work forward.

"The way that I see it there are two really neat applications," says Medford. "The first is finding environmental pollutants and the second is finding inexpensive ways to do security. For ordinary people this could be quite empowering simply to know whether their air and water is clean."
New Scientist