Background • Infectious diseases represent the most serious threat to shrimp farming. The economic impact from mass mortalities in shrimp farming has intensified to prompt the development of strategies to overcome and control disease outbreaks. • Researchers developed a panel to measure hemocyte expressed genes involved in the immune defense of shrimp • Standard BioTools RT-qPCR technology provided a high- throughput platform to simultaneously measure expression levels for several genes during the time course study
Methods • Data was collected using the 96.96 GE IFC on the Biomark system with EvaGreen® (DNA intercalating dye) chemistry • Real-Time PCR Analysis Software was used to obtain Ct values and set a cutoff of two-fold change in expression level for analysis • Pathogen-free shrimp were injected with lethal doses of WSSV and F. solani, separately, and gene expression levels were measured and compared with a control group over a time course of 24–48 hours • A total of 68 hemocyte-expressed genes of broad relevance to the immune system were chosen
Results • WSSV infection showed upregulation of 11 genes and downregulation of 11, while three showed time-dependent changes in gene expression • F. solani infection showed downregulation of most modulated genes • Some genes analyzed were selective in their changes in expression, dependent upon the pathogen Conclusions • Molecular signatures identified uncovered promising RNAi pathways • The transcriptional signatures identified here can serve as immunomarkers of mortality events • At the time of publication, this was the first report of a global gene expression profile of immune response of infected shrimp on the brink of death
Results and conclusions