Scientists have identified a gene that improves the heat tolerance of the algae that live symbiotically with coral species, and could potentially help the corals adapt to some warming.
Symbiodinium is a unicellular algae that provides its coral host with photosynthetic products in return for nutrients and shelter.
However, high sea temperatures can cause the breakdown of this symbiotic relationship and lead to the widespread expulsion of Symbiodinium from host tissues, an event known as coral beaching. If bleached corals do not recover, they starve to death, leaving only their white, calcium-carbonate exoskeleton.
Now, researchers from King Abdullah University of Science and Technology in Saudi Arabia have identified special genes, called retrotransposons, which could help the algae adapt more rapidly to heat stress.
During their study, most genes commonly associated with heat stress were turned off, while a small number of retrotransposons were turned on.
The team suggests that the activation and replication of Symbiodinium’s retrotransposons in response to heat stress could lead to a faster evolutionary response, “since producing more mutations increases the chance of generating a beneficial one that allows the symbionts to cope better with this specific stress,” said geneticist and principal investigator, Manuel Aranda.