RNA Interference Applied to Crustacean Aquaculture

Abstract

RNA interference (RNAi) is a powerful tool that can be used to specifically knock-down gene expression using double-stranded RNA (dsRNA) effector molecules. This approach can be used in aquaculture as an investigation instrument and to improve the immune responses against viral pathogens, among other applications. Although this method was first described in shrimp in the mid-2000s, at present, no practical approach has been developed for the use of dsRNA in shrimp farms, as the limiting factor for farm-scale usage in the aquaculture sector is the lack of cost-effective and simple dsRNA synthesis and administration procedures. Despite these limitations, different RNAi-based approaches have been successfully tested at the laboratory level, with a particular focus on shrimp. The use of RNAi technology is particularly attractive for the shrimp industry because crustaceans do not have an adaptive immune system, making traditional vaccination methods unfeasible. This review summarizes recent studies and the state-of-the-art on the mechanism of action, design, use, and administration methods of dsRNA, as applied to shrimp. In addition, potential constraints that may hinder the deployment of RNAi-based methods in the crustacean aquaculture sector are considered.

Keywords: RNAi; anti-viral; dsRNA; gene-silencing; immunology; innate immunity; miRNA; nanoencapsulation; shrimp; siRNA.

Figure 1

Simplified RNAi mechanism. (A) Initiation step and (B) effector step.

Figure 2

Schematic representation of RNAi pathways (exogenous and endogenous), including siRNA (RISC) and miRNA (RITS) pathways. Different RNA effector molecules (dsRNA, siRNA, and miRNA) are delivered into the cells (gills, hemocoel, intestine lumen, and hepatopancreas) through viral receptors, SID-1, and/or by clathrin-mediated endocytosis.

Figure 3

Potential routes of production and delivery of dsRNA to farmed shrimp.

Figure 4

RNAi technology applied to shrimp reproductive issues. (A) Generation of all-male offspring. (B) Alternative method to eyestalk ablation.