DAO 67:155-162 (2005)  -  doi:10.3354/dao067155

A PCR-based diagnostic assay for the detection of Roseovarius crassostreae in Crassostrea virginica affected by juvenile oyster disease (JOD)

Aaron P. Maloy1, 3, Bruce J. Barber2,4, Katherine J. Boettcher1,*

1Department of Biochemistry, Microbiology, and Molecular Biology, and 2School of Marine Sciences, University of Maine, Orono, Maine 04469, USA
3Present address: U.S. Geological Survey, Lake Ontario Biological Station, Oswego, New York 13126, USA
4Present address: Eckerd College, Galbraith Marine Science Laboratory, St. Petersburg, Florida 33711, USA
*Corresponding author. Email:

ABSTRACT: We have developed a PCR-assay for the diagnosis of juvenile oyster disease (JOD) based on the detection of Roseovarius crassostreae directly from affected oysters. Species-specific primers are used to amplify the 16S-23S rDNA internal transcribed spacer (ITS) of R. crassostreae, and confirmation of product identity is accomplished by restriction enzyme analysis. No false positives were obtained with either closely related bacterial species or from other DNAs present in oyster samples. The assay has the potential to detect as few as 10 cells of R. crassostreae per oyster when samples are taken from the inner valve surfaces of the animal. Inclusion of material from soft body surfaces is not necessary, and may reduce sensitivity approximately 10-fold. In a JOD-affected population, a positive PCR result was obtained from all oysters from which these bacteria were subsequently cultured. The assay also detected the presence of R. crassostreae in 2 oysters from which no R. crassostreae isolates were recovered. No R. crassostreae was detected by either PCR or bacteriology in oysters from a population that was not exhibiting JOD-signs. This assay is expected to advance regional disease management efforts and provide valuable insights into the disease process and epizootiology of JOD.

KEY WORDS: Juvenile oyster disease · JOD · Roseobacter · PCR · Crassostrea virginica · Roseovarius crassostreae

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