Nov. 9 (UPI) — Using the CRISPR-Cas9 technique to precisely alter the genome of Great Barrier Reef coral, scientists identified a gene vital to heat tolerance in the species Acropora millepora.
The discovery, detailed Monday in the journal PNAS, could aid efforts to safeguard coral reef ecosystems from the effects of climate change.
“We developed an improved CRISPR-Cas9 method that allowed us to test gene function in coral for the first time,” lead study author Philip Cleves said in a news release.
“As a proof-of-concept, we used CRISPR-Cas9 genome editing to understand the function of a key gene that influences the ability of coral to survive heat,” said Cleves, principle investigator in the department of embryology at the Carnegie Institute for Science.
Coral reefs around the world have been degraded by bleaching events, which have been triggered by longer, more frequent and more intense marine heatwaves. But not all coral species have suffered equally — some species have shown a greater resiliency than others.
“Understanding the genetic traits of heat tolerance of corals holds the key to understanding not only how corals will respond to climate change naturally but also balancing the benefits, opportunities and risks of novel management tools such as selective breeding and movement of corals among reefs,” said co-author Line Bay, researcher at the Australian Institute of Marine Science.
Earlier gene-editing technologies were too imprecise to isolate and manipulate individual genes — and do the kind of experiments that made the latest study possible.
However, the CRISPR-Cas9 system works like surgical scissors, capable of turning off specific genes or swapping them out for alternative snippets of DNA.
For the new study, scientists silenced HSF1, the Heat Shock Transcription Factor 1 gene, which previous studies have shown plays an important role in the heat tolerance of other organisms.
The modified coral larvae proved healthy when water temperatures in the lab remained stable at 27 degrees Celsius. When researchers heated the tanks to 34 degrees, however, the coral larvae perished.
Conversely, unedited coral larvae persisted, despite the elevated water temperatures.
“By removing the gene, and then exposing the coral larvae to heat stress, we demonstrated that the modified coral larvae died whereas the unmodified larvae were unharmed under the increased temperature,” said co-author Dimitri Perrin.
“This result shows the key role HSF1 plays in coral coping with rising temperatures,” said Perrin, a data scientist at the University of Queensland in Australia.
Researchers suggest insights provided by CRISPR-Cas9 — and even the editing tool itself — could prove useful to coral reef preservation and restoration efforts.