Abstract:

In order to understand vertical transmission of DsCPV and its role in sustained controlling pine caterpillars,this study was undertaken to develop the assay technique for detection of DsCPV in early stage of infection of pine caterpillars,based on the reverse transcription of RNA followed by the polymerase chain reaction amplification (RT-PCR).A pair of primers producing 614bp amplification fragment were designed based on the sequence of the C-polyhedrin gene of Bombyx mori CPV (BmCPV),and the expected amplification products were obatined when genomic dsRNAs isolated from purified BmCPV,DsCPV and Lymantria dispar CPV (LdCPV) were used as templates.Genomic dsRNAs isolated from Heliothis armigera CPV and DNAs from Lymantria dispar nuclear polyhedrosis virus (LdNPV) and DNAs from midgut tissue of healthy Dendrolimus spectabilis (Walker) larva did not yield any amplification products.The detection limit of purified DsCPV genomic dsRNAs was 1.0pg.The nucleotide sequence of the 614bp DNA amplification product from DsCPV was 87% homogenous with the corresponding part of C-polyhedrin gene of BmCPV.These results demonstrated that BmCPV,DsCPV and LdCPV were homologous as classfied in the same electropheres type I,and that this RT-PCR assay could be used for early,rapid,sensitive and specific detection of DsPCV infection in the natural population of the pine moth,due to the apparent different feeding habits of Bombyx mori,Dendrolimus ssp.and Lymantria dispar larva each other and the no infection of BmCPV and LdCPV to Dendrolimus ssp.

Key words: DsCPV, Polyhedrin gene, RT-PCR