The Oyster industry in Australia is one of the biggest contributing industries to Aquaculture. Sydney rock oyster (SRO) industry in particular has been severely affected by Queensland Unknown (QX) disease outbreaks, which is caused by a single celled protozoan, Marteilia sydneyi. Continuous outbreaks of this disease pose great risk for the sustenance of the industry, and hence development of disease resistant lines holds the key for the future of the industry. In 1990s NSW Department of Primary Industries started a selective breeding programme to develop a line of QX resistant SRO by performing interbreeding amongst the survivors of the QX outbreak. These oysters showed good disease resistance, but very little is known about the molecular mechanisms involved.

Previous studies have revealed that genes for disease resistance are heritable, so molecular level knowledge, will be a great help in the development of disease resistant lines. Using Marker assisted selection. We have performed proteomic comparison of QX resistant selected lines with Wild type oysters, using both 2D electrophoresis and label free shotgun proteomics. To get an insight into disease progression, we analysed the temporal proteomic variation of n=20 oysters of each type, collected from Hawkesbury River at two different time points during the disease progression. In an initial study using 2D gel comparison of QX resistant lines and wild type oysters, we found 38 proteins to be significantly (p<0.05) altered in expression in the disease resistant oysters. Quantitative label free shotgun proteomics will also be performed on the same protein samples to substantiate the findings further.