Inhibition of Penaeus monodon densovirus replication in shrimp by double-stranded RNA

Stunted shrimp caused by Penaeus monodon densovirus (PmDNV) infection is one of the main problems leading to a significant economic loss in Thailand. To control this pandemic disease, a double-stranded-RNA-mediated virus-specific gene silencing approach was applied to inhibit viral replication. In this study, two dsRNAs corresponding to the non-structural protein (ns1) and the structural protein (vp) genes of PmDNV were synthesized and introduced into shrimp haemolymph prior to viral challenge. After allowing viral replication for two weeks, the suppression effect by each dsRNA was evaluated by semi-quantitative PCR and compared with the control. A reduction of PmDNV in shrimp treated with each dsRNA was observed. In contrast, a high level of viral infection was detected in the control group (NaCl). Based on a limited sample number, we reached the tentative conclusion that virus-specific dsRNA can inhibit PmDNV replication, in which the dsRNA-ns1was more effective than the dsRNA-vp.