Persistence and expression of Cotesia congregata polydnavirus in host larvae of the tobacco hornworm, Manduca sexta.

摘要: The gregarious braconid wasp Cotesia congregata parasitizes host larvae of Manduca sexta, and several other sphingid species. Parasitism induces immunosuppression due to the disruptive action wasp's polydnavirus (PDV) on blood cells. During initial stages parasitism, these cells undergo apoptosis followed by cell clumping, which clears hemolymph a large number In this study, persistence expression PDV (CcPDV) were examined using Southern Northern blots, respectively. Digoxygenin-labelled total polydnaviral DNA was used probe genomic isolated from fat body brains hosts with emerged wasps taken 6 days following egress parasitoids, significant cross-hybridization between viral seen. Thus, virus persists in for duration even during post-emergence period, may be integrated caterpillar DNA. Viral gene blots probes rubecula CrV1 homolog, CrV1-like mRNAs expressed as early 4 h post-parasitization at least 72 faint hybrization is seen time eclose. contrast, Pieris rapae transcript only brief time, hemocyte function disrupted. effect transitory, hemocytes regain their normal functions after parasites emerge first instars.The genome CcPDV contains one copy homolog shown conjunction our earlier studies PDV-encoded protein 1, current work suggests multiple transcripts are produced parasitization host, likely target induce apoptosis, thereby preventing encapsulation parasitoid's eggs. Whether DNAs host's remains proven, but results provide preliminary evidence that detected emergence later.