An improved gene-editing tool could improve the understanding of the genetic basis of disease resistance in valuable species of farmed fish, according to research conducted at the Roslin Institute in the U.K.

Roslin Institute researchers developed an optimized technique to efficiently introduce changes in fish cell cultures in the laboratory, an announcement from the institute said.

They used cells of Atlantic salmon, rainbow trout and Chinook salmon, which together are worth $22 billion a year to the aquaculture industry.

The gene-editing tool, which is fast and efficient compared with existing techniques, could be used to investigate specific genes involved in the response to pathogens, and the role of these genes in natural variation in disease resistance in fish populations, the institute said.

"This improved editing technique has allowed us to investigate specific candidate genes involved in resistance to pathogens for Atlantic salmon and rainbow trout, leading to insight into the functional basis of disease resistance in these important aquaculture species," noted Dr. Yehwa Jin with Roslin.

Improved gene editing

More than 90% of cells can be edited with the method and the protocol takes approximately half the time required for existing gene-editing methods, according to Roslin.

The editing method uses a complex molecule formed of a combination RNA and a protein known as CRISPR/Cas9, responsible for cutting DNA. These molecules — called ribonucleoprotein complexes — have shown potential for gene editing in previous studies in other species, Roslin explained.

The researchers applied an electrical field to the ribonucleoprotein complexes, which increased the permeability of the fish cell membrane and allowed DNA to be introduced into cells.

The cell cultures in the study are widely used in genetics and immunology studies of fish species.

"Genetically engineering fish cells in the lab is very challenging because the cells grow slowly and there is currently no efficient way to introduce DNA in them. This new method circumvents these challenges. It is simple, fast and efficient, and we have shown that it can be used in genetic studies of important aquaculture species," said Dr. Remi Gratacap with the Roslin Institute.

The study was jointly led by Roslin scientists Gratacap and Jin, with input from masters student Marina Mantsopoulou, who works in the research group of professor Ross Houston. It is published in the journal Marine Biology and has been funded by the Biotechnology & Biological Sciences Research Council, part of UK Research & Innovation.