Brain corals have the genes to outsmart the heat

Through a world-first genomics research project convened by the Great Barrier Reef Foundation, scientists have discovered a key genetic difference in some types of corals that may make them better equipped to withstand and survive heat stress.

In a new paper published in international journal Genome Biology, researchers from the Sea-quence project: ReFuGe 2020 Consortium report on the unique capacity of ‘robust’ corals like brain and mushroom corals to generate an essential amino acid that other corals categorised as ‘complex’ don’t possess.

This extra amino acid means ‘robust’ corals are less dependent on their external food sources than the ‘complex’ corals such as the staghorn corals.

All coral species are host to Symbiodinium – microscopic algae – that provide them with the energy they need to build their hard skeletons and also some of their essential amino acids.

Under stress from heat, the coral animal expels its resident Symbiodinium, which also gives the coral its colour. The result is coral bleaching.

Because brain corals and other robust corals can make at least one of the essential amino acids, they are therefore less reliant on their Symbiodinium to survive.

This new research suggests they are more resilient to the impacts of bleaching than their ‘complex’ coral counterparts as a result.

Great Barrier Reef Foundation Managing Director Anna Marsden said an international collaboration provided the foundation for this significant research discovery.  .

"This scientific knowledge breakthrough is an outcome of a five year research collaboration with leaders in coral reef science and management, including the Australian National University, James Cook University, the Australian Institute of Marine Science, the University of Queensland, the Great Barrier Reef Marine Park Authority, Bioplatforms Australia, the King Abdullah University of Science and Technology (Saudi Arabia), and the Great Barrier Reef Foundation," Ms Marsden said.

"Understanding how we can boost resilience to climate change is the key to the survival of coral reefs.

"This discovery provides more hope for the survival of coral reefs globally."

The project was supported by funding from Bioplatforms Australia through the Australian Government National Collaborative Research Infrastructure Strategy (NCRIS), Rio Tinto, the Fitzgerald Family Foundation and the Australian Government.

“This project achieved a world first in sequencing the entire coral genome including the coral animal and its associated Symbiodinium,” said Andrew Gilbert, Bioplatforms Australia General Manager.

“It also developed a new method of sequencing coral genomes, fast tracking the process exponentially and setting the path for more corals around the world to also be sequenced,” he said.

“Importantly, the power of this partnership has made the genetic data from nine different coral species from the Great Barrier Reef freely available to researchers all over the world,” Ms Marsden added.

“This will hopefully be the first of many new discoveries that could unlock more genetic secrets to ensuring the future of our coral reefs.”

The newly published research was led by Dr Hua (Emily) Ying of the Australian National University and Prof. David Miller of the ARC Centre of Excellence for Coral Reef Studies at James Cook University.