SYDNEY, March 9 (Xinhua) -- Australian scientists on Monday said they have made a major discovery of how some invasive plants make a better comeback after fires to out-compete native species for resources, pointing to improved revegetation efforts in large areas hit by bushfires and mining.
During bushfires, organic compounds called karrikins are produced from burning plant material; karrikins soak into the soil with the first rain after a fire and stimulate the germination of buried seeds, according to a statement from the Australian Research Centre of Excellence in Plant Energy Biology research facility.
Scientists from the center and the University of Western Australia analyzed more than 400 plant species and found that some appeared to have developed an enhanced sensitivity to the compounds, the center said.
Plants use a special receptor known as KAI2 to detect karrikins, but unlike most species that carried only a single type of KAI2, some species had more receptors, lead researcher Mark Waters said.
"We looked at plants we knew responded well to karrikins and found that one of these, an Australian weed commonly called wild turnip, had three KAI2 receptors," Waters said.
"On closer examination we found that mutations in one of these three receptors were responsible for the improved karrikin sensing."
The scientists also found that by changing two amino acids in the KAI2 receptor of a plant they could turn it into a "karrikin super-sensor," he said.
"This is exciting because we have discovered a way in which KAI2 protein can evolve to change its sensitivity to karrikins," Waters said.
"It will be interesting to see if this discovery could be used in areas where revegetation efforts are needed."
Australia has been hit by a 2019-2020 bushfire season that has claimed more than 30 lives across the country and more than 5 million hectares of bushland in New South Wales state alone.
Of the 400 plant species they examined, the scientists found that there were similar KAI2 mutations in nine species of flowering plants.
"One of these species is Hakea drupacea, an Australian native that has become an invasive weed in South Africa, and relies on fire to spread," Waters said. The latest findings were published in scientific journal Nature Communications.
By understanding which native species are karrikin super-sensors the scientists hope their study can guide predictions of which plant species may germinate best when treated with karrikins and apply this knowledge to the revegetation of fire-affected land, according to the center.
