Proteomic clues to the identification of QX disease-resistance biomarkers in selectively bred Sydney rock oysters, Saccostrea glomerata

Evidence that the major hemolymph protein of the Pacific oyster, Crassostrea gigas, has antiviral activity against herpesviruses

“…6). Previous research has demonstrated that the hemolymph concentration of Saccostrea glomerata EcSOD, the orthologue of C. gigas cavortin, is elevated in oysters selected for disease resistance (Green et al, 2009;Simonian et al, 2009).…”

Disease Prevention Strategies for QX Disease (Marteilia sydneyi) of Sydney Rock Oysters (Saccostrea glomerata)

“…Determining the risk factors that result in QX disease outbreaks will allow farmers to position their farms in locations where QX disease outbreaks are unlikely to occur. Immunological studies have revealed the importance of heavy summer rainfall as a risk factor for QX disease outbreaks and the importance of antioxidant enzymes (PO, EcSOD, and Prx6) in the resistance of S. glomerata to M. sydneyi (Butt & Raftos 2008, Simonian et al 2009a). The Sydney rock oyster breeding program is now investigating whether oysters can be selected for disease resistance based on their phenoloxidase phenotype (O'Connor & Dove 2009), but selection of oysters for lowsalinity tolerance may be an alternative selection strategy for QX resistance.…”

“…In QX-resistant S. glomerata, the basal expression of an extracellular superoxide dismutase (EcSOD) is higher, and the basal expression of peroxiredoxin 6 (Prx6) is lower when compared with nonselected oysters ). This observation is supported by complementary proteomic and mass spectrometry analysis of the hemolymph proteins from QX-resistant and nonselected oysters (Simonian et al 2009a). The expression of these 2 antioxidant genes could not be induced by microbial invasion ), leading to the hypothesis that another mechanism used by S. glomerata selectively bred for QX resistance is their ability to generate the antiparasitic compound hydrogen peroxide (H 2 O 2 ) at a faster rate and higher concentration when challenged with disease agents.…”

“…In terms of immune responses, S. glomerata that are resistant to M. sydneyi have higher titers of the defensive enzyme phenoloxidase and increased expression of the gene encoding extracellular superoxide dismutase, but reduced expression of peroxiredoxin 6 (Butt & Raftos 2008, Simonian et al 2009a). Melanization of pathogens by phenoloxidase is a major innate defense system in invertebrates (Cerenius & Soderhall 2004).…”

Elucidating the life cycle of Marteilia sydneyi, the aetiological agent of QX disease in the Sydney rock oyster (Saccostrea glomerata)

“…In the absence of data on transmission and the causative elements that promote these outbreaks, this has been the most conservative course of action and, until recently, the only management tool available to protect the SRO industry. However, with reports indicating that M. sydneyi is present in most estuaries in which major SRO culture is undertaken (Adlard and Wesche, 2005), even though many have never suffered significant disease events, research has turned to investigating the contribution of oyster immuno-competence to disease inhibition (Bezemer et al, 2006;Butt and Raftos, 2008;Green et al, 2009;Dang et al, 2011), the production of QX disease-resistant oysters (Nell et al, 2000;Nell, 2001;Green et al, 2008) and disease resistance biomarkers (Simonian et al, 2009). …”