Plants emit animal-like signals when stressed out

Plant stress
CC BY 2.0 whologwhy/Flickr

Say it isn’t so! Or say it is. Either way, researchers show that plants respond to their surroundings in a way similar to mammals.

Those of us who subside on a diet without meat are often met with the snarky refrain of our carnivorous comrades: “But it’s ok to kill innocent plants?” To which we generally reply with a well-practiced roll of the eyes. So although I’m reluctant to add fodder to the smirking meat-eaters’ fire, here goes … because it’s just so cool.

Researchers at the University of Adelaide have shown for the first time that when plants encounter stress, they use signals that are normally associated with animals. Although plants (thankfully) don’t have a nervous system, they respond to their environment with a similar mix of chemical and electrical responses as do animals. But they do it with “machinery” that is specific to plants.

The team examined wheat, grape vine, rice and barley and found that all of the plants tested responded in the same way to stresses like acidic soil, flooding and intense heat.

Matthew Gilliham, senior author and associate professor at the University of Adelaide, says plants seem to use gamma-aminobutyric acid (GABA) to regulate electrical signals that can then control their growth.

"It's a parallel between animals and plants that we didn't know existed," he said.

"We've known for a long-time that the animal neurotransmitter GABA (gamma-aminobutyric acid) is produced by plants under stress, for example when they encounter drought, salinity, viruses, acidic soils or extreme temperatures," says Gilliham.

"But it was not known whether GABA was a signal in plants. We've discovered that plants bind GABA in a similar way to animals, resulting in electrical signals that ultimately regulate plant growth when a plant is exposed to a stressful environment."

By figuring out how plants respond to GABA, the researchers say that they are optimistic about the potential for working with plants and how they respond to stress, and how that could lead to things like more productive farming.

The findings could prove a boon to medical research as well, they say. The similarity might explain why some drugs that are derived from plants – like particular sedatives and anti-epileptics – work in humans; the drugs can interact with proteins in the GABA-signaling system in both plants and animals.

"Plants may look different,” Gilliham says, “but they still use some of the same messengers, and that's fascinating.”

(Fascinating as long as they don’t get scared when they see a sauté pan.)

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