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July 1, 2013

Australia

RNA Interference Remarkably Effective

at Protecting Shrimp Against Mortality

 

From Abstract: The potential of RNA interference (RNAi) approaches to inhibit viral replication and thus protect shrimp against diseases of significant economic importance has inspired a lot of recent research and investment.  As shrimp cells possess the RNAi machinery needed to cleave long double-stranded (ds)RNAs into short-interfering (si)RNAs capable of specific mRNA destruction, optimizing systems for dsRNA delivery and longevity are now the major obstacles to commercial application in shrimp.  At Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO), tail-muscle injection of juvenile Black Tiger shrimp (Penaeus monodon) with a cocktail of 5 dsRNAs targeted to different regions across the ORF1a-1b gene of gill-associated virus (GAV) was found to be remarkably effective at protecting shrimp against mortality following GAV challenge.  A 12 days post-challenge, 97% of dsRNA-injected shrimp remained alive compared to only 10% of saline-injected controls.  Quantitative PCR analysis confirmed that this was due to GAV replication being inhibited.

 

Based on the success of the GAV-challenge bioassays, proof-of-concept experiments are now proceeding to determine whether muscle injection of the GAV dsRNA cocktail can reduce or clear chronic moderate-level GAV infection as found commonly in wild broodstock captured in north Queensland for use in hatcheries.  Once demonstrated in juveniles, the method will be applied with broodstock in hatchery environments to examine for any impacts on reproductive output as well as reduced vertical transmission levels of GAV infection to progeny.

 

In this talk we will describe the approaches we have been used to select GAV target sites for maximum efficacy as well as progress made to date in protecting shrimp against GAV challenge and in clearing natural GAV injections from broodstock to limit transmission occurring in hatcheries.

 

Source: The Thumb Drive Containing the Abstracts from Aquaculture 2013 (February 21-25, 2013, Nashville, Tennessee, USA).  Information: John Cooksey, World Aquaculture Conference Management, P.O. Box 2302, Valley Center, California 92082 USA (phone 1-760-751-5005, fax 1-760-751-5003, email worldaqua@aol.com).  RNA Interference to Clear Viral Infection from Shrimp.  Melony J. Sellars (melony.sellars@csiro.au, CSIRO Food Futures Flagship, CSIRO Marine and Atmospheric Research, 41 Boggo Road, Dutton Park, Queensland, Australia 4102) Min Rao and Jeff A. Cowley.  February 2013.

 

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