A study from The University of Western Australia has revealed a previously unknown process that plants can make their own “secret decisions” on how much carbon can be released back into the atmosphere.
The study published in Nature Plants suggests that the discovery has “profound implications” for the use of plants as carbon stores. It means that plants of the future could be designed to meet the world’s food needs while also aiding the environment.
“We found that plants control their respiration in a way we did not expect, they control how much of the carbon from photosynthesis they keep to build biomass by using a metabolic channel,” University of Western Australia plant biochemist Harvey Millar and author of the study told ScienceAlert.
“This happens right as the step before they decide to burn a compound called pyruvate to make and release COtwo back to the atmosphere.”
The process was discovered while working on a classic plant model organism called thale cress (Arabidopsis thaliana).
The researchers, led by the University of Western Australia plant molecular scientist Xuyen Le, labeled pyruvate with C13 (a carbon isotope) to track where it was being shifted during the citric acid cycle, and found that pyruvate from different sources was being used differently.
This means that plant can actually track the source of the pyruvate and act accordingly, choosing to either release it, or hold on to it for other purposes.
“We found that a transporter on mitochondria directs pyruvate to respiration to release CO2, but pyruvate made in other ways is kept by plant cells to build biomass – if the transporter is blocked, plants then use pyruvate from other pathways for respiration,” Le said told Science Alert.
“Imported pyruvate was the preferred source for citrate production.”
The study suggests that this ability to make decisions breaks the normal rules of biochemistry, where typically, every reaction is a competition, and the processes don’t control where the product goes.
“Metabolic channelling breaks these rules by revealing reactions that don’t behave like this, but are set decisions in metabolic processes that are shielded from other reactions,” says Millar.
(With inputs from agencies)
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