Acute hepatopancreatic necrosis disease (AHPND) has emerged as a major debilitating disease that causes massive shrimp death resulting in substantial economic losses in shrimp aquaculture. Given that several diseases and infections have been associated with microRNAs (miRNAs), we conducted a comparative transcriptomic analysis using the AHPND (VA) and non-AHPND (VN) strains of Vibrio parahemolyticus to identify miRNAs potentially involved in AHPND pathogenesis in Litopenaeus vannamei. A total of 83 miRNAs (47 upregulated and 36 downregulated) were significantly differentially expressed between the VA and VN challenged groups, while 222 target genes of these miRNAs were predicted. Functional enrichment analysis revealed that the miRNAs target genes were involved in multiple biological processes including metabolic pathways, amoebiasis, Vibrio cholerae infection etc. Finally, interaction network and qPCR (Real-time Quantitative PCR) analysis of 12 potential key AHPND-related miRNAs and their predicted target genes, revealed their possible involvement in modulating several immune-related processes in the pathogenesis of AHPND. We have shown using comparative transcriptomic analysis, miRNAs and their target genes that are responsive to AHPND V. parahemolyticus infection in shrimp, therefore suggesting their possible role in defense response to AHPND V. parahemolyticus infection.

White spot syndrome virus (WSSV) is a large, enveloped, double-stranded DNA virus that threatens shrimp aquaculture worldwide. So far, the mechanisms of WSSV-host interactions are ill-defined. Recent studies have revealed that IE1, an immediate-early protein of WSSV, is a multifunctional modulator implicated in virus–host interactions. In this study, the functions of IE1 were further explored by identifying its interacting proteins using GST-pull down and mass spectrometry analysis. A total of 361 host proteins that potentially bind to IE1 were identified. Bioinformatics analysis revealed that the identified IE1-interactors wereinvolved in various signaling pathways such as prophenoloxidase (proPO) system, PI3K-AKT, and MAPK. Among these, the regulatory role of IE1 in shrimp proPO system was further studied. The Co-immunoprecipitation results confirmed that IE1 interacted with the Ig-like domain of Penaeus vannamei proPO or proPO-like protein (hemocyanin). Additionally, we found that knockdown of IE1 reduced viral genes expression and viral loads and increased the hemocytes’ PO activity, whereas recombinant IE1 protein inhibited the PO activity in a dose-dependent manner. Finally, we demonstrated that WSSV could suppress the hemocytes’ PO activity at the early infection stage. Collectively, our current data indicate that IE1 is a novel viral regulator that negatively modulates the shrimp proPO system.

Shrimp aquaculture is an essential economic venture globally, but the industry faces numerous challenges, especially pathogenic infections. As invertebrates, shrimp rely mainly on their innate immune system for protection. An increasing number of studies have shown that ubiquitination plays a vital role in the innate immune response to microbial pathogens. As an important form of posttranslational modification (PTM), both hosts and pathogens have exploited ubiquitination and the ubiquitin system as an immune response strategy to outwit the other. This short review brings together recent findings on ubiquitination and how this PTM plays a critical role in immune modulation in penaeid shrimps. Key findings inferred from other species would help guide further studies on ubiquitination as an immune response strategy in shrimp-pathogen interactions.