TRANSCRIPTION OF POLYDNAVIRUS GENES IN THE OVAIRES OF ICHNEUMONID HYPOSOTER DIDYMATOR

Syed H.H. Rizvi

Abstract


Some endoparasitic wasps like Hyposoter didymator lay eggs in lepidopteran larvae along with polydnaviruses which disturb the immune system and physiology of the host and thus allow successful parasitism. Polydnaviruses have been divided into two genera, Ichnoviruses (IV) and Bracoviruses (BV), found in Ichneumonidae and Braconidae respectively. Ichnoviruses contain some important genes families like the repeat element genes (rep genes) family. Different genes of this family have different levels of transcriptions. Thirty rep genes have been described in H. didymator IV (HdIV) up to now. Nine HdIV rep genes in H. didymator females were analyzed by real time PCR and found different levels of transcriptions of rep genes in the wasp’s ovary while in the head and thorax the transcription was very low. All the 9 rep genes are transcribed in the wasps ovaries, one of them, rep8, being transcribed at very low level. This pattern of transcription in the wasp was compared with results obtained with the same 9 rep genes in Lepidoptera (Galibert et al., 2006). Comparison indicates that rep1 is transcribed in both Lepidoptera and Hymenoptera whereas rep2, rep4, rep7 seem to be preferentially transcribed in the wasps. These differences in transcription may be due to different functions of the genes in different tissues.

Keywords


Hyposoter didymator, polydnavirus, repeat element genes, transcription level, ichnoviruses, endoparasitic relation

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References


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