Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Workshop: Aquaculture
The eastern oyster Crassostrea virginica has two major diseases: Dermo caused by the parasite Perkinsus marinus and MSX by Haplosporidium nelsoni. Effects of infection in C. virginica range from reductions in condition index, haemolymph protein concentrations and lysozyme activity to decline in reproductive output, retarded growth and death. MSX-resistant strains of C. virginica have been developed at Rutgers University, and the Pacific oyster C. gigas appears to be resistant to both diseases. At present, however, we know little about molecular mechanisms of infection and host defense against the two parasites. We have begun a study searching for genes involved in host response to Dermo and MSX infections, through the use of subtractive hybridizations. For Dermo, controlled artificial infections are conducted in both C. virginica and C. gigas. Samples of hemolymph and gills were collected both in challenged and control oysters for mRNA extraction. Subtractive libraries were then performed to compare the two populations of mRNA and obtain clones of specific genes that are expressed only in infected oysters. For MSX, infected wild oysters and uninfected resistant oysters, which were naturally exposed to the parasite, were used to construct the library. Selected clones from these libraries are being sequenced. Results from the sequence analysis will be presented at the meeting.