Comparative Proteomics of Ostreid Herpesvirus 1 and Pacific Oyster Interactions With Two Families Exhibiting Contrasted Susceptibility to Viral Infection

Abstract

Massive mortality outbreaks affecting Pacific oysters (Crassostrea gigas) spat/juveniles are often associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted using two contrasted Pacific oyster families for their susceptibility to viral infection. Live oysters were sampled at 12, 26, and 144 h post infection (hpi) to analyze host-pathogen interactions using comparative proteomics. Shotgun proteomics allowed the detection of seven viral proteins in infected oysters, some of them with potential immunomodulatoy functions. Viral proteins were mainly detected in susceptible oysters sampled at 26 hpi, which correlates with the mortality and viral load observed in this oyster family. Concerning the Pacific oyster proteome, more than 3,000 proteins were identified and contrasted proteomic responses were observed between infected A- and P-oysters, sampled at different post-injection times. Gene ontology (GO) and KEGG pathway enrichment analysis performed on significantly modulated proteins uncover the main immune processes (such as RNA interference, interferon-like pathway, antioxidant defense) which contribute to the defense and resistance of Pacific oysters to viral infection. In the more susceptible Pacific oysters, results suggest that OsHV-1 manipulate the molecular machinery of host immune response, in particular the autophagy system. This immunomodulation may lead to weakening and consecutively triggering death of Pacific oysters. The identification of several highly modulated and defense-related Pacific oyster proteins from the most resistant oysters supports the crucial role played by the innate immune system against OsHV-1 and the viral infection. Our results confirm the implication of proteins involved in an interferon-like pathway for efficient antiviral defenses and suggest that proteins involved in RNA interference process prevent viral replication in C. gigas. Overall, this study shows the interest of multi-omic approaches applied on groups of animals with differing sensitivities and provides novel insight into the interaction between Pacific oyster and OsHV-1 with key proteins involved in viral infection resistance.

Genetic markers associated with divergent selection against the parasite Marteilia cochillia in common cockle (Cerastoderma edule) using transcriptomics and population genomics data

“…Thus, searching for those genetic markers was considered a main goal for recovering cockle production and preventing its expansion to other areas through breeding programs or appropriate shellfishery management. Similar approaches have been tackled for the identification of molecular markers for disease resilience in other mollusc species (de la Ballina et al, 2018;Ronza et al, 2018;Farhat et al, 2020;Lepretre et al, 2021).…”

ADAR-Editing during Ostreid Herpesvirus 1 Infection in Crassostrea gigas : Facts and Limitations

“…The sustained expression of oyster ADAR1 up to 10 days after IP suggested a continuous protein production, as a possible counteraction of the instability of ADAR, as showed for human protein due to SUMOylation ( 15 ). The absence of ADAR1 in proteomic data of OsHV-1 infected oysters ( 16 ) possibly confirmed a rapid degradation. Although protein–protein interactions are mostly unknown in bivalves, it is possible that proteins other than ADAR1 can either interact with it or compete for the same dsRNA substrates, as shown for the enzymatic inactive human ADARB2 ( 13 ).…”

Viral dUTPases: Modulators of Innate Immunity

“…Genes encoding for putative dUTPases have been identified in members of the Alloherpesviridae [ 59 , 60 , 61 ] and Malacoherpesviridae [ 62 , 63 , 64 ] ( Table 1 ). Annotation of these genes indicates that they encode for proteins that exhibit the common motif order (I, II, III, IV, and V) suggesting a homotrimeric structure.…”