Résumé
The endoparasitoid ichneumonid wasp Hyposoter didymator relies on Endogenous Viral Elements (EVEs) for its development. Its chromosomes contain viral sequences that become active during the pupal stage in a specific tissue of the female reproductive tract called the calyx. This activation leads to the production of thousands of virus particles, which are secreted into the female oviduct and transferred to the parasitoid’s host during egg laying. With the availability of the H. didymator genome, EVEs have been previously annotated, revealing the presence of more than 60 viral loci dispersed in the 12 wasp chromosomes (Lorenzi et al. 2024, doi: 10.1371/journal.ppat.1011980.). We also annotated essential genes for insect development and physiology, including transcription factors from the Hox and Hepatocyte nuclear factor families, as well as genes involved in ecdysone and juvenile hormone-signaling and other hormone-related genes (neuropeptide receptors and their ligands).In this study, we aimed to identify key regulators of the endogenous virus replication by comparing the replicative tissue (calyx) with a non-replicative tissue (oviduct) throughout wasp pupal development. We used microdissection to separate the calyx and the oviduct tissues from more than 500 insects across three pupal stages (five replicates per stage). To analyze the full gene expression profile of the wasp, these samples were sequenced using RNA-Seq, and differentially expressed genes were identified by comparing the two tissues at each time point and by tracking expression changes over time in both tissues.Our analysis revealed 3,405 differentially expressed genes out of 14,975, grouped into 13 clusters based on shared expression patterns each revealing enrichments of peculiar biological processes or molecular functions. Notably, two clusters contained nearly all EVE genes, while eight differentially expressed transcription factors and hormone receptors were distributed across six clusters.