摘要
A recombinant Helicoverpa armigera nucleopolyhedrovirus （HearNPV） ex- pressing the insect-selective neurotoxin （RjAalTjO from Cuban scorpion Rhopalurus junceus was constructed by replacing the UDP-glucosyltransferase gene （egt） using ）^- red homologous recombination system. Another egt deleted control HearNPV was con- structed in a similar way by inserting egfp gene into the egt locus. One-step viral growth curve and viral DNA replication curve analysis confirmed that the recombination did not affect the viral growth and DNA replication in host cells. There is no discernable differ- ence in occlusion-body morphogenesis between RjAalTf-HearNPV,, Egfp-HearNPV and HZ8-HearNPV, which was confirmed by transmission electron microscopy analysis. How- ever, the insecticidal activity of RjAal 7f-HearNPV is enhanced against the third instar H. armigera larvae according to the bioassay on virulence comparison. There is a dramatic reduction （56.9%） in median lethal dose （LD50） and also a reduction （13.4%） in median sur- vival time （ST50） for the recombinant RjAalTf-HearNPV compared to the HZ8-HearNPV, but only a 27.5% reduction in LD50 and 10.1% reduction in ST50 value when Egfp- HearNPV is compared with HZ8-HearNPV. The daily diet consumption analysis showed that the RjAal 7f-HearNPV was able to inhibit the infected larvae feeding compared with the egt minus HearNPV. These results demonstrated that this novel recombinant RjAa17f- HearNPV could improve the insecticidal effect against its host insects and RjAa17fcould be a considerable candidate for other recombinant baculovirus constructions.
A recombinant Helicoverpa armigera nucleopolyhedrovirus （HearNPV） ex- pressing the insect-selective neurotoxin （RjAalTjO from Cuban scorpion Rhopalurus junceus was constructed by replacing the UDP-glucosyltransferase gene （egt） using ）^- red homologous recombination system. Another egt deleted control HearNPV was con- structed in a similar way by inserting egfp gene into the egt locus. One-step viral growth curve and viral DNA replication curve analysis confirmed that the recombination did not affect the viral growth and DNA replication in host cells. There is no discernable differ- ence in occlusion-body morphogenesis between RjAalTf-HearNPV,, Egfp-HearNPV and HZ8-HearNPV, which was confirmed by transmission electron microscopy analysis. How- ever, the insecticidal activity of RjAal 7f-HearNPV is enhanced against the third instar H. armigera larvae according to the bioassay on virulence comparison. There is a dramatic reduction （56.9%） in median lethal dose （LD50） and also a reduction （13.4%） in median sur- vival time （ST50） for the recombinant RjAalTf-HearNPV compared to the HZ8-HearNPV, but only a 27.5% reduction in LD50 and 10.1% reduction in ST50 value when Egfp- HearNPV is compared with HZ8-HearNPV. The daily diet consumption analysis showed that the RjAal 7f-HearNPV was able to inhibit the infected larvae feeding compared with the egt minus HearNPV. These results demonstrated that this novel recombinant RjAa17f- HearNPV could improve the insecticidal effect against its host insects and RjAa17fcould be a considerable candidate for other recombinant baculovirus constructions.
