Protein markers of Marteilia sydneyi infection in Sydney rock oysters, Saccostrea glomerata.

Marteilia sydneyi is the causative agent of QX disease in Sydney rock oyster, Saccostrea glomerata. It is responsible for disease outbreaks among oysters that occur during summer and can result in up to 95% mortality. QX disease has significantly decreased S. glomerata production in some areas of Australia's eastern seaboard over the past 30 years. Marteilia sydneyi sporulates in the digestive gland of oysters leading to complete disorganization of the infected tissues. The current study used proteomics to identify potential molecular markers of sporulating M. sydneyi infection during a field trial undertaken in the Georges River, Sydney, between December 2006 and May 2007. Early stages of M. sydneyi infection were detected by polymerase chain reaction, whilst cytological examination was used to identify sporulating M. sydneyi in the gut. Protein expression in oyster haemolymph was assessed during the M. sydneyi infection period by two dimensional electrophoresis. Proteome maps identified significant differences in the expression of four proteins in oysters with sporulating M. sydneyi infections.