Sterile salmon by targeting factors involved in germ cell survival: novel vaccination strategies for sustainable fish farming (Sketch 40)

The Salmosterile project has developed new methods for making sterile salmon in farming based on knockdown and knockout technology. The project has taken advantage of the information from the salmon genome, and has found a protein, Dead end, which is essential for the formation of germ cells in salmon. We have made germcell free fish in the project by destroying the dead gene or its transcript. Furthermore, we have seen that the germcell free fish grows as well as normal immature farmed fish. We have also seen that the germcell free fish do not enter maturation. Through knockout and knockdown we are now trying to establish and scale up a biotechnological solution for sterile salmon production. In addition, the project has identified and functionally studied a variety of other proteins that contribute to the reproduction in salmon and zebrafish. This applies to both genes that encode factors that influence the formation, survival and migration of the genital stem cells at early stages of development - as well as genes that are important for the initiation of puberty and survival of the genital cells later in life. In addition, the project has establised a protocol for knockout of genes in salmon with the help of Crispr-Cas9. The project has developed a protocol for knockdown in salmon. In addition, methods for molecules uptake in salmon eggs have been established.

Salmon farming is a key-industry in Norway, with first hand value above thirty billion NOK per year, and more than twenty thousand people employed directly and indirectly. The salmon industry is a driving force for biotechnological applications in the mar ine sector, and ongoing sequencing of the Atlantic salmon genome offers new opportunities to solve major aquaculture bottlenecks. Genetic impact of escaped farmed salmon on wild populations is regarded as a major environmental problem, currently preventin g further expansion of the Norwegian salmon industry. To solve this problem, we propose to explore integrative biotechnological approaches to develop vaccination strategies for sterility in farmed salmon. Two approaches for vaccination will be tested; tar geting survival of primordial germ cells in embryos by vaccinating female broodstock, or targeting germ cell development and survival in juvenile fish by interfering with somatic germ cell communication. To this end, vaccination towards known candidate pr oteins will be attempted, together with search for new candidate genes and gene products. In parallel, the function of selected genes will be explored by gene editing and gene knock down techniques using both salmon and zebrafish. The project involves str ong industry participation along the value chain from research, to vaccine development and testing and implementation in both breeding and grow-out companies. It is expected that the project will provide spin-offs to solve related problems, e.g. by provi ding new knowledge on new vaccination technologies, GMO-models, and new delivery technologies for antigens and antisense molecules. At the same time, the involved technologies call for ethical, legal and societal considerations, which will be dealt with b y specific ELSA expertise in an integrated approach, in close interaction with the entire Consortium.