DEVELOPMENT OF Chlamydomonas reinhardtii FOR CONTROL WHITE SPOT SYNDROME VIRUS IN SHRIMP (Penaeus vannamei)

 White spot disease (WSD), caused by a white spot syndrome virus (WSSV), is the most serious viral disease in shrimp which leads a high mortality rate in many crustaceans. Basically, an effective infection of the virus emerged from the interaction between WSSV envelope proteins and host cell surface protein receptors, hence, the major envelope proteins that play a key role in the initial step of WSSV infection is VP28. It is known that VP28 is a favorable candidate for immumostimulant induction in shrimp. In this study, the application of a single cell, green-microalga (Chlamydomonas reinhardtii) is being used as a cell factory for recombinant protein production. A transgenic C. reinhardtii was generated in order to produce VP28 and aimed to stimulate shrimp immunity through orally administration. The codon optimized VP28 containing C-terminus histidine fusion tag was synthesized and cloned into chloroplast expression vector, pASapI. Subsequently, the expression vector was transformed into C. reinhardtii chloroplast and the authenticity of recombinant 6×His-VP28 was determined by VP28 specific antibodies.

Transgenic microalgae containing recombinant VP28 was fed to shrimp to control WSD and stimulate an immune response. Oral administration with feed containing transgenic VP28 algal meal demonstrated a significant higher survival rate whereas no survival was observed in infected shrimp fed with controls (normal and transformant with empty vector) after WSSV infection. These results indicated that the protection was VP28 specific and shrimp immunity could not be induced by the cell components of C. reinhardtii. In this present study, the development of this microalgae expressed recombinant protein can reduce the mortality rate of shrimp. This technique will be provided a new method for the prevention of other diseases in aquatic animals.