The M.bicoloratus Parasitism Promotes The Interaction Of CypD And P53 And Induces Apoptosis Of The Host Hemocytes

Microplitis bicoloratus is the natural enemy of Spodoptera Litura.(S.Litura),and,It can inhibit host immune response and growth by parasitizing S.litura larvae.Cyclophilin D(CypD)is a member of the cyclophilin family.Studies have shown that CypD-p53 interaction can induce apoptosis through the mitochondrial pathway during mammalian cells are exposed to apoptotic signals.To study the molecular mechanism of Microplitis bicoloratus bracovirus(MbBV)inducing apoptosis of host hemocytes to inhibit cellular immunity in the process of S.lituraMicroplitis parasitized by Microplitis bicoloratus(M.bicoloratus),the expression,interaction,apoptosis and mitochondrial changes of CypD and p53 were detected by apoptosis detection,Western blot,Co-IP,immunofluorescence,gene silencing and mitochondrial potential detection during parasitization and MbBV infection.The results showed that the parasitization promoted expression and interaction of CypD and p53 and caused the decrease of mitochondrial membrane potential,the release of cytochrome C from mitochondria,the activation of caspase 3,which leading to host hemocyte aopotosis.When the Spli221 cells were infected by MbBV,the Similar results were obtained as above.Furthermore,silencing of CypD can rescue the apoptotic hemocytes induced by parasitization.At the same time,during the CypD was inhibited by CsA or silenced by siRNA,we found that the CypD-p53 interaction was weadened,the mitochondrial membrane potential was recovered and the cell apoptosis decreased significantly.These results suggest that MbBV can induce apoptosis by promoting the interaction of CypD and p53.In summary,this study clarified that the parasitism promoted CypD-p53 interaction,redued the mitochondrial membrane potential,released cytochrome C from mitochondria,activated caspase 3 and caused the host hemocyte aopotosis.These findings will allow for the further understanding ofthe role that MbBV-CypD signaling plays in MbBV-induced host hemocyte apoptosis and may provide a new research target for biological control of Spodoptera litura.