In order to save water, plants might be able to use an animal relaxing gene.
A team of Australian and German researchers, led by Bo Xu of the Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, found that the GABA molecule, which is usually associated with relaxation in animals, can help the plant control the size of leaf pores to prevent water loss.
Key research points
- Plants and animals share a relaxing gene called GABA
- In plants, GABA signals leaf pores to remain closed when drought-stressed
- Closed pores prevent water loss
“GABA minimised pore openings in a range of crops such as barley, broad bean and soybean, and in lab plants that produce more GABA than normal,” says Matthew Gilliham, director of the Waite Research Institute at the University of Adelaide.
“This led to the lab plants using less water from the soil and surviving longer in the drought experiments.
“We found plants that produce lots of GABA reduce how much their pores open, thereby taking a smaller breath and reducing water loss.”
GABA is usually used by animals as a nerve signal, where it acts as a small chemical message to tell the brain and body to relax.
Previously, researchers found that GABA also acted as a receptor in plants. In their paper, published in Nature Communications, they show that the GABA tells the plants to keep pores closed when it has experienced drought stress previously, in order to save water.
“Both plants and animals produce GABA and they put it to different uses,” says Xu.
“Plants don’t have nerves, instead they appear to use GABA to match their energy levels with their response to the environment.
“GABA doesn’t close pores on leaves like other stress signals, it acts in a different way – how much a plant accumulates GABA when it is stressed determines how much it applies the brake pedal to reduce the pore opening the following morning, and water loss that day – like a stress memory of the day before.”
This stress response could be a target for researchers to help plants help themselves when it comes to overcoming drought.
“I’ve been studying how plants regulate their stomatal pores for over 35 years,” says Rainer Hedrich, of the University of Würzburg.
“To find a completely new and unexpected way that they are regulated has certainly been one of our most surprising discoveries. I look forward to seeing how this translates out in the field.”
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