What if your house plant could tell you your water isn’t safe? Scientists are closer to realising this, having successfully engineered a plant to turn beet red in the presence of a banned, toxic pesticide. To achieve this, researchers from the University of California, Riverside, had to solve an engineering puzzle: how to enable a plant to sense and react to a chemical in the environment, without damaging its ability to function normally in all other respects.
“The biggest piece here is we’ve created an environmental sensor without modifying the plant’s native metabolism,” says Ian Wheeldon, associate professor of chemical and environmental engineering at UCR, adding, “Previously, the biosensor component would have messed up the plant’s ability to grow toward light or stop using water when stressed. This won’t.”
The engineering process begins with a protein called abscisic acid, or ABA, that helps plants acclimate to stressful changes in the environment.
During a drought, soil dries and plants produce ABA. Additional proteins, called receptors, help the plant recognise and respond to ABA, which in turn tells the plant to close pores in its leaves and stems to minimise evaporation, and the plant is less likely to wilt.
Last year, the research team demonstrated that ABA receptor proteins can be trained to bind to chemicals other than ABA. Now the team has shown that once the receptors bind to this other chemical, the plant will turn beet red. For this demonstration, the team used azinphos-ethyl, a pesticide found to be toxic to humans. “The people we work with are trying to sense information about chemicals in the environment from a distance,” says Sean Cutler, UCR professor of plant cell biology. “If you had a field of these and they turned red, that would be pretty obvious, visually,” he adds.
As part of the same experiment, the research team also demonstrated the ability to turn another living organism into a sensor: yeast. The team was able to show a response in yeast to two different chemicals at the same time. However, this is not yet possible in plants.
“It would be great if we could eventually design one plant to sense 100 banned pesticides, a one-stop shop,” says Cutler, adding, “The more you can stack, the better, especially for applications involving environmental health or defense. But there are limits to what we can engineer for these new sensing capacities at this time.”
(Source: UCR)