The white spot syndrome virus (WSSV) is a highly pathogenic virus that has been wreaking havoc on the global shrimp aquaculture industry, causing significant mortality rates in farmed shrimp. Despite efforts to develop viral suppression methods, the disease remains a major challenge.
However, recent advancements in genome editing technology using CRISPR/Cas9 have opened new possibilities for preventing and treating viral diseases. In an innovative study, researchers from the University of Phayao, the Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), and Mahidol University successfully applied the CRISPR/Cas9 system to suppress WSSV infection in the shrimp Penaeus vannamei, paving the way for a potential paradigm shift in shrimp industry management.
CRISPR/Cas9 for Disease Control
CRISPR/Cas9, a powerful tool for precise genetic engineering, has the potential to revolutionize disease control in aquaculture. By targeting specific viral genes, CRISPR/Cas9 can disrupt the virus’s replication cycle, preventing its spread and reducing mortality rates.
How Does CRISPR/Cas9 Work?
CRISPR/Cas9 is a powerful tool that enables scientists to precisely edit an organism’s DNA. It consists of two key components:
- Guide RNA (gRNA): This RNA molecule guides the Cas9 enzyme to a specific DNA sequence.
- Cas9 Enzyme: This enzyme acts as molecular scissors, cutting the DNA at the target site.
By designing specific gRNAs, researchers can target and cleave viral DNA, effectively disrupting the virus’s replication cycle.
A Synergistic Approach
However, delivering CRISPR/Cas9 machinery to shrimp cells presents a challenge. To overcome this, scientists are using virus-like particles (VLPs) as efficient delivery vehicles. VLPs are tiny, harmless particles that mimic viruses but lack the ability to replicate. They can be designed to carry CRISPR/Cas9 components directly to shrimp cells.
The combination of CRISPR/Cas9 and VLPs offers a promising strategy for developing WSSV-resistant shrimp. By targeting specific viral genes and stimulating the shrimp’s immune response, this approach could significantly reduce disease outbreaks.
Constructing a Chimeric DNA Vector
The study, published in Scientific Reports, involved constructing a chimeric DNA vector that combined the shrimp U6 promoter with gRNA expression sequences specific to two sites of the WSSV genome and the WSSV ribonucleotide reductase promoter with the Cas9 DNA sequence. This vector was designed to express WSSV genome-specific gRNAs and Cas9 in primary cultured hemocyte cells and shrimp tissue.
Researchers used RT-PCR to determine gRNA and Cas9 expression in cells and tissue, discovering that the CRISPR/Cas9 system could cleave WSSV DNA amplicons in vitro. Additionally, shrimp receiving the CRISPR/Cas9-WSSV treatment showed significantly lower WSSV DNA levels compared to untreated shrimp.
Enhancing the Immune Response
The study also revealed that the CRISPR/Cas9-WSSV system not only interfered with viral DNA spread but also stimulated a genetic response related to the immune system. When treated with CRISPR/Cas9-WSSV, shrimp showed a significantly longer survival period when challenged with WSSV.
Implications for the Shrimp Industry
These findings have significant implications for the development and application of CRISPR/Cas9 technology in controlling WSSV infectious diseases. The study demonstrates the potential of this technology to manage shrimp aquaculture and reduce the economic burden of WSSV-related losses in the industry.
Conclusion
In conclusion, the application of CRISPR/Cas9 technology to suppress WSSV infection in shrimp has shown promising results, offering a new approach to controlling this devastating disease. As the global shrimp aquaculture industry continues to face challenges, this breakthrough has the potential to revolutionize how we manage shrimp farming and ensure a sustainable and healthy supply of this important food source.
Contact
Charoonroj Chotwiwatthanakun
Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University
Rama VI Rd, Bangkok, 10400, Thailand
Mahidol University, Nakhonsawan Campus, Nakhonsawan, 60130, Thailand
Email: charoonroj.cho@mahidol.ac.th
Reference (open access)
Pudgerd, A., Saedan, S., Santimanawong, W. et al. Genome editing of WSSV CRISPR/Cas9 and immune activation extends the survival of infected Penaeus vannamei. Sci Rep 14, 26306 (2024). https://doi.org/10.1038/s41598-024-78277-7
