Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Aquaculture
            

DIFFERENTIAL GENE EXPRESSION IN EASTERN OYSTERS, CRASSOSTREA VIRGINICA, EXPERIMENTALLY INFECTED WITH THE PROTOZOAN PARASITE PERKINSUS MARINUS

¹ Department of Fisheries, Animal and Veterinary Science, University of Rhode Island, Woodward Hall, Kingston, RI 02881, USA

² Departmento de Biología Celular, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain

Perkinsus marinus is a protozoan parasite responsible for widespread mortality of the Eastern oyster, Crassostrea virginica. In order to elucidate the molecular responses of the oyster to parasitic infection, we used suppression subtractive hybridization to monitor the induced expression of genes involved in the response of oysters to experimental infection by P. marinus. Perkinsus-free oysters were injected with artificial seawater or cultured P. marinus cells. Hemocytes were collected at 4, 24, 96 hours, and 2 months after injection. Two libraries of infection-related genes were constructed by subtracting pools of cDNA isolated from hemocytes of non-infected oysters to pools of cDNA from hemocytes of infected oysters. Differential screening analysis showed the enrichment of approximately 20% non-infected -specific and 50% infected -specific cDNAs. Sequence comparisons with the protein database showed that the non-infected -specific library (containing genes down-regulated in the process of infection) included genes with similarity to proteins involved in metabolism, signaling factors or receptors, a membrane associated protein, and immune function proteins. The infected -specific library (genes up-regulated in the process of infection) contained included genes coding for arginine kinase, a phosphotransferase involved in the utilization and storage of energy that has been proposed as a marker of disease and tissue damage, and several genes with similarity to proteins with immune function. Further screening of the libraries will allow the identification of a large amount of gene candidates for studies in oyster immunity and host-pathogen interactions.