Project description:To better understand the pathogenesis of OsHV-1 and to determine which cell pathways might be affected during OsHV-1 infection, we used an experimental infection in the Pacific oyster Crassostrea gigas by intra-muscular injection with a low or high load of OsHV-1. Animals were sampled 2 days post-injection (dpi) which corresponds to the incubation period required for OsHV1 to initiate an intense replication phase. Twenty-five abundant proteins linked to infection process were identified using a two-dimensional electrophoresis (2-DE) proteomic approach.
Project description:Massive mortalities have been observed in France since 2008 on spat and juvenile Pacific oysters, Crassostrea gigas. A herpes virus called OsHV-1, easily detectable by PCR, has been implicated in the mortalities as demonstrated by the results of numerous field studies linking mortality with OsHV-1 prevalence. Moreover, experimental infections using viral particles have documented the pathogenicity of OsHV-1. The physiological responses of host to pathogen are not well known. In this study, a number of genes involved in the response to viral challenge have been identified and can be considered as confirmation of the role of the virus in the observed mortality. The aim of this study was to understand mechanisms brought into play against the virus during infection in the field. A microarray assay has been developed for a major part of the oyster genome and used for studying the host transcriptome. Spat with and without detectable OsHV-1 infection were compared by microarray during mortality episodes. The result allowed establishment of a hypothetic scheme of the host cell’s infection by, and response to, the pathogen. This response seems to be different to “sensu stricto” innate immunity through genic regulation of the virus life cycle. . Some regulatory response against the virus may explain that some oysters are able to survive infection by regulation of the viral genes associated with the OsHV-1 life cycle.
Project description:Deep sequencing of mRNA from Pacific oyster Crassostrea gigas Competent larvae of Crassostrea gigas were treated with epinephrine solution, and then sampled at different time intervals. For shell damage experiment, shell were broken and then tissues were sampled at different time intervals.
Project description:Ostreid Herpesvirus type 1 (OsHV-1) has become a serious infective agent of the Pacific oyster livestock worldwide. In particular, the OsHV-1 muVar subtype has been associated to severe mortality episodes concerning Crassostrea gigas in France and other regions of the world such as Australia and New Zealand. Factors triggering productive infections and virus interactions with susceptible and resistant bivalve hosts are not completely understood though some studies have been undertaken to explore the genes expressed in oysters after infection. We took advantage of an highly infected oyster sample to perform an in-vivo dual RNA-seq analysis. An extremely high sequencing coverage allowed us to explore in detail the Herpesvirus genome and transcriptome, and to identify viral-activated molecular pathways in Crassostrea gigas, thus expanding the current knowledge on the host-virus interactions.
