Survivability of Penaeus monodon during white spot syndrome virus infection and its correlation with immune related genes

Abstract

At present the most common and most devastating disease of shrimp is caused by the white spot syndrome virus (WSSV), which has spread throughout the world mainly by the different species of crustaceans carrying the virus. Although considerable progress has been made in the molecular characterisation of WSSV, little information is available on shrimp genes which are involved in WSSV infection. To develop a better understanding of the shrimp antiviral defences and possibly develop new control measures for WSSV, differential expression of immune related genes in haemocytes was studied. Gene expression of penaeidins, crustin, lysozyme, C-type lectin, prophenoloxidase-1, prophenoloxidase-2 and haemocyanin in Penaeus monodon following experimental infection with WSSV was studied and the time-dependent pattern was determined. The study showed the general trend of upregulation of five (penaeidins, lysozyme, C-type lectin, prophenoloxidase-1, prophenoloxidase-2) of the seven genes at the early hours of infection. Animals surviving beyond 84h following WSSV infection showed higher levels of expression of genes encoding lysozyme, C-type lectin, penaeidins, prophenoloxidase-1 and prophenoloxidase-2 than those animals which died before 60h, indicating a genetic basis in disease resistance. The gene expression level can therefore be used as a biomarker for selecting broodstocks for better resistance to WSSV infection, thus promising a role in the fight against WSSV along with other management measures.