Possible repair of UV-damaged Spodoptera littoralis nucleopolyhedrovirus DNA via generation of mutant carrying photolyase gene with DNA repair activity

Background Baculoviruses can be inactivated by ultraviolet (UV) light, which limits their application as an efficient biopesticide. In an attempt to enhance virus resistance to UV inactivation, a photolyase gene, isolated from Spodoptera litura granulovirus (SpliGV), was expressed in a photolyase deficient Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) and the infectivity of recombinant virus expressing phr gene was determined after exposure to UV irradiation. Results Expression of the photolyase resulted in a fivefold resistance of virus occlusion bodies of the recombinant virus (vSpli-phr) compared to the wild type SpliNPV upon exposure to UV irradiation as measured by LC50 value when fed on S. littoralis neonate. Furthermore, the recombinant virus expressing phr showed a significant decrease in the time required for lethality than the control virus with about 22 h, as measured by ST50 value. Hence, expression of photolyase via vSpli-phr relatively may rescue the viral DNA damage caused by UV irradiation. Conclusions This study provided the evidence that the generated recombinant virus encoding a functioning photolyase, which may have implications for the development of a new generation of baculoviruses with enhanced insect pest management capabilities.