Plants signal stress when they’re affected by drought, high temperatures or a disease using the same chemical and electrical signals that animal use. In animals, these chemicals and signals are delivered, carried and interpreted by the nervous system, which is why it’s surprising to find plants use this mechanism. The “machinery”, however, is different suggesting plants and animals separately evolved the same communication mechanism.

When faced by drought, a plant will send a chemical signal across its cells to change the way the plant grows and uses resources. Image: Flickr

When an animal is stressed, its brain releases the GABA (gamma-aminobutyric acid) neurotransmitter which signals the body it needs to enter defense mode, conserve resources and so on. The researchers at  Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology now report that plants also use GABA to signal stress and regulate plant growth.

This newfound knowledge may prove to be essential in securing food, considering plants are under a heightened risk of stress at the face of climate change.

“The major stresses agricultural crops face like pathogens and poor environmental conditions account for most yield losses around the planet – and consequently food shortages,” says co-lead author Prof. Stephen Tyerman.

“By identifying how plants use GABA as a stress signal we have a new tool to help in the global effort to breed more stress resilient crops to fight food insecurity.”

Considering the findings, it’s not surprising anymore that  plant-derived drugs used as sedatives and anti-epileptics work in humans, where they interact with the GABA signaling system. Closely studying GABA signaling plants might render some interesting medical findings.

What’s also interesting is that the plants have found a way to essentially migrate the GABA neurotransmitter from cell to cell. But while the compound is the same for both animals and plants, the receptors are different, as reported in Nature Communication.

“This raises very interesting questions about how GABA has been recruited as a messenger in both plant and animal kingdoms,” says co-lead author Sunita Ramesh. “It seems likely that this has evolved in both kingdoms separately.”