Droughts have posed a serious threat to plant life in recent years and have cost farmers billions of dollars, but a new "reprogramming" method could help relieve some of these woes.

When plants experience a drought they produce abscisic acid (ABA), which is a stress hormone that stunts plant growth and reduces water consumption, the University of California - Riverside reported. Crops could be sprayed with ABA to protect them during a drought, but this can be extremely expensive. Researchers have been working to create synthetic ABA, but this can also be costly and time consuming.

Agrochemical mandipropamid is already widely used to control late-season diseases in crops, but this new research suggests it could be used to prompt drought-threatened plants to show an ABA response when "programmed" to do so.

A team of researchers worked with Arabidopsis, a model plant often used in plant biology labs, and the tomato plant. They used synthetic biological methods to birth a new version of these plants' abscisic acid receptors that were activated by mandipropamid instead of ABA. 

"We successfully repurposed an agrochemical for a new application by genetically engineering a plant receptor - something that has not been done before," said Sean Cutler, an associate professor of botany and plant sciences. "We anticipate that this strategy of reprogramming plant responses using synthetic biology will allow other agrochemicals to control other useful traits - such as disease resistance or growth rates, for example."

Protein engineering is a method that allows researchers to construct protein variants and test for new properties of these variants. The team used this method to create modified plant receptors into which mandipropamid could easily fit and prompt activation. The engineered plants proved to respond to mandipropamid as if they were being treated by ABA and did not show significant differences from non-engineered plants.

"We have, in effect, circumvented this hurdle using synthetic biology - in essence, we took something that already works in the real world and reprogrammed the plant so that the chemical could control water use," Cutler concluded.

The findings were published in a recent edition of the journal Nature.