CRISPR/Cas9 reveals a key gene involved in the evolution of coral skeleton formation

Newswise — Baltimore, MD—A recent study headed by Carnegie's Phillip Cleves employs advanced CRISPR/Cas9 gene editing technology to unveil a crucial gene necessary for the formation of stony corals' reef structures. The findings are published in the Proceedings of the National Academy of Sciences.

Stony corals, as marine invertebrates, construct substantial skeletons that serve as the foundation for reef ecosystems. These hubs of biodiversity accommodate approximately 25% of recognized marine species.

"Coral reefs possess immense ecological significance," stated Cleves. "However, human activities have led to their deterioration. The carbon emissions we release into the atmosphere contribute to the warming of the oceans, leading to detrimental bleaching incidents. Additionally, these emissions modify seawater chemistry, causing ocean acidification, which hampers the growth of reefs."

Gradually, the surplus carbon dioxide emitted into the atmosphere through the combustion of fossil fuels is absorbed by the ocean. In the water, it undergoes a reaction that produces an acidic compound, which poses a corrosive threat to coral, shellfish, and various other marine organisms.

Stony corals face susceptibility to ocean acidification primarily due to their reliance on the calcification process for the construction of their skeletons using calcium carbonate. As the pH of the surrounding water decreases, this process becomes progressively challenging. Given the pivotal role of coral skeleton formation in reef development, significant research efforts have been directed towards comprehending the genetic mechanisms governing this process and its evolutionary aspects in corals.

Cleves' laboratory has been utilizing the Nobel Prize-winning CRISPR/Cas9 technology for several years to explore cellular and molecular processes that could contribute to coral conservation and restoration endeavors. In a noteworthy instance, they previously unveiled a gene essential for a coral's response to heat stress, providing valuable insights that could aid in predicting how corals will cope with impending bleaching incidents.

In their recent research, Cleves' team, which includes Amanda Tinoco from Carnegie, employed genome editing techniques to establish the essential role of a specific gene known as SLC4γ in initiating the skeletal construction of young coral colonies. The protein encoded by this gene facilitates the transportation of bicarbonate across cellular membranes. Notably, SLC4γ is exclusively found in stony corals and not in their non-skeleton-forming counterparts. These findings collectively suggest that stony corals utilized the unique gene, SLC4γ, as part of their evolutionary process for skeleton formation.

Cleves concluded, "By employing state-of-the-art molecular biology methods to address urgent environmental challenges, we can uncover the genes responsible for crucial ecological characteristics." He added, "Through the development of these genetic tools for studying coral biology, we can significantly enhance our comprehension of their intricate mechanisms and acquire valuable insights to implement successful conservation initiatives for these delicate ecosystems."

Earlier this year, Cleves received recognition from The Pew Charitable Trusts as one of the distinguished recipients of the 2023 Pew Fellowship in Marine Conservation. Notably, he became the inaugural researcher to be granted the organization's Marine and Biomedical Science Fellowship. This prestigious program aims to provide support for research endeavors that employ methodologies or technologies predominantly utilized in biomedical science to advance marine conservation efforts.

The study involved collaboration with several co-authors, including Lorna Mitchison-Field from Carnegie, Jacob Bradford and Dimitri Perrin from Queensland University of Technology, Christian Renicke and John Pringle from Stanford University, and Line Bay from the Australian Institute of Marine Science. Their collective contributions enriched the research and broadened its scope across different institutions.