Insects possess specific immune responses to protect themselves from different types of pathogens.Activation of immune cascades can inflict significant developmental costs on the surviving host.To characterize infecti...Insects possess specific immune responses to protect themselves from different types of pathogens.Activation of immune cascades can inflict significant developmental costs on the surviving host.To characterize infection kinetics in a surviving host that experiences baculovirus inoculation,it is crucial to determine the timing of immune responses.Here,we investigated time-dependent immune responses and developmental costs elicited by inoculations from each of two wild-type baculoviruses,Autographa californica multiple nucleopolyhedrovirus(AcMNPV)and Helicoverpa zea single nucleopolyhedrovirus(HzSNPV),in their common host H.zea.As H.zea is a semi-permissive host of AcMNPV and fully permissive to HzSNPV,we hypothesized there are differential immune responses and fitness costs associated with resisting infection by each virus species.Newly molted 4th-instar larvae that were inoculated with a low dose(LD15)of either virus showed signify icantly higher hemolymph FAD-glucose dehydrogenase(GLD)activities compared to the corresponding control larvae.Hemolymph phenoloxidase(PO)activity,protein concentration and total hemocyte numbers were not increased,but instead were lower than in control larvae at some time points post-inoculation.Larvae that survived either virus inoculation exhibited reduced pupal weight;survivors inoculated with AcMNPV grew slower than the control larvae,while survivors of HzSNPV pupated earlier than control larvae.Our results highlight the complexity of immune responses and fitness costs associated with combating different baculoviruses.展开更多
基金the United States Department of Agriculture(AFRI 2017-67013-26596)awarded to GWF and KHNational Science Foundation(IOS-1645548)awarded to GWF,IS,and KH+1 种基金and Hatch Project PEN04576(GWF and KH).QP thanks the financial support from China Scholarship Council(grant 201506300111)Natural Sciences and Engineering Research Council of Canada Postdoctoral Fellowship(NSERC PDF-488105-2016).
文摘Insects possess specific immune responses to protect themselves from different types of pathogens.Activation of immune cascades can inflict significant developmental costs on the surviving host.To characterize infection kinetics in a surviving host that experiences baculovirus inoculation,it is crucial to determine the timing of immune responses.Here,we investigated time-dependent immune responses and developmental costs elicited by inoculations from each of two wild-type baculoviruses,Autographa californica multiple nucleopolyhedrovirus(AcMNPV)and Helicoverpa zea single nucleopolyhedrovirus(HzSNPV),in their common host H.zea.As H.zea is a semi-permissive host of AcMNPV and fully permissive to HzSNPV,we hypothesized there are differential immune responses and fitness costs associated with resisting infection by each virus species.Newly molted 4th-instar larvae that were inoculated with a low dose(LD15)of either virus showed signify icantly higher hemolymph FAD-glucose dehydrogenase(GLD)activities compared to the corresponding control larvae.Hemolymph phenoloxidase(PO)activity,protein concentration and total hemocyte numbers were not increased,but instead were lower than in control larvae at some time points post-inoculation.Larvae that survived either virus inoculation exhibited reduced pupal weight;survivors inoculated with AcMNPV grew slower than the control larvae,while survivors of HzSNPV pupated earlier than control larvae.Our results highlight the complexity of immune responses and fitness costs associated with combating different baculoviruses.
