Plants send animal-like stress signals, research shows

Winter wheat crop growing in a field.
Winter wheat crop growing in a field.
Image: Robert Harding/Associated Press

Plants exhibit stress in a surprisingly similar way to animals, including humans, researchers have found.

The scientists, whose findings were published Wednesday in the science journal Nature Communications, discovered plants use many of the same chemical and electrical signals that animals employ when under stress, despite not having a nervous system. Namely, the animal neurotransmitter gamma-aminobutyric acid (GABA).

There's been speculation over the past 20 years that GABA was a signal in plants, one of the researchers, associate professor Matthew Gilliham of the University of Adelaide, told Mashable Australia. It was known, for example, that GABA concentration increases rapidly in plants from even low level stresses, such as an insect crawling up a leaf.

Beyond confirming the presence of GABA in plants, however, the team found plants bind GABA in a way that results in electrical signals that can regulate plant growth.

Working with wheat, rice, grape vine and barley, the team discovered that a range of plants appear to respond similarly to stresses such as extreme heat, acidic soil or flooding. "Plants seem to have recruited GABA to regulate electrical signals that can then control their growth," he said. "It's a parallel between animals and plants that we didn't know existed."

Unlike humans who can run and hide, plants just have to sit there and take anything nature throws at them — they have to adapt or die. "They've developed these response systems that allow them to change how they live for a period of time. For example, change growth rate or metabolism," Gilliham said.

The team are now working on modifying the responses of plants to GABA, and testing how they can help them cope with unfriendly conditions. "By understanding GABA, we could start to understand the factors that impinge on the yield of plants like wheat or barley," he said.

The pharmaceutical industry already uses GABA for depression, anxiety, and sleep disorder medications. Now that we know plants respond to GABA in a similar way to animals, it could also explain why plant-derived drugs work so well in humans. "The parallels means there is the potential for new discoveries," he added.

"Both plants and animals have recruited the same messenger," Gilliham said. "Plants may look different, but they still use some of the same messengers, and that's fascinating."