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Virus-derived piRNAs in Lepidoptera and efficacy of RNAi in the pest species Helicoverpa armigera

Book - Dissertation

RNA interference (RNAi) is an important post-transcriptional regulatory pathway in insects. In the moths and butterflies (order: Lepidoptera), it regulates protein translation by sequestering or degrading mRNAs. The target mRNAs are recognised through complementary small-RNAs (sRNAs) bound to the effector proteins, endoribonucleases from the "Argonaute" family. The RNAi system can be subdivided into three branches, based on the sRNA biogenesis pathways and the Argonaute proteins involved. These are the siRNAi, the piRNAi and the miRNAi pathways. While piRNAi is involved in silencing transposable elements, siRNAi is the main antiviral immune pathway in insects. Recent evidence suggests that the piRNAi pathway might also be involved in antiviral immunity in Lepidoptera, although the mechanism remains unknown. To this end, we seek to unravel the antiviral role of piRNAs in Lepidoptera. Additionally, the RNAi system has become a useful tool for functional research in insects, as it allows to (temporarily) knock-down specific transcript levels. However, Lepidoptera are often insensitive to RNAi. Therefore, a second goal is to assess the useability of RNAi in the pest species Helicoverpa armigera.
Publication year:2023