Glyptapanteles indiensis is a polydnavirus-carrying wasp that parasitizes the larval stage of the gypsy moth, Lymantria dispar. During parasitization, G. indiensis injects its eggs along with the polydnavirus (GiPDV) into L. dispar. Within host tissues, viral genes are expressed that function to suppress the host’s immune response and to ensure successful parasitism. Knowledge of GiPDV gene expression in the parasitized host is limited. Previous studies in our laboratory reported partial GiPDV DNA is integrated in vitro within the chromosomal DNA of cells derived from L. dispar. One of the GiPDV circular viral segments involved with integration was sequenced and a polydnavirus gene (p297) was identified and cloned (see accompanying poster). Here we analyze expression of this gene in the parasitized L. dispar host using one step RT-PCR and evaluate gene expression levels in different host tissues using RT quantitative competitive PCR (RT-qcPCR). GiPDV p297 could be detected in the host as early as 2 hours post parasitization and continued for 8 days. GiPDV p297 gene was expressed in the tissues of the larval host hemolymph, brain, and fat body. The highest level of expression was in hemolymph. Moderate expression was observed in the brain of the host. The weakest expression was observed in fat body of the host. The high expression in host hemolymph, together with the abundant expression of the gene at an early stage of parasitization (2 h pp) suggested that the GiPDV gene product may be involved in disruption of the host immune system and protection of endoparasitoid egg from encapsulation.
Species 1: Hymenoptera Braconidae Glyptapanteles indiensis
Species 2: Lepidoptera Lymantriidae Lymantria dispar
Keywords: Polydanvirus, gene expression, quantitative RT-PCR
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