Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR 7261, CNRS - Université de Tours, Tours, France.
Université de Tours, Département des Microscopies, Tours, France.
J Virol. 2022 Jul 13;96(13):e0052422. doi: 10.1128/jvi.00524-22. Epub 2022 Jun 9.
Nudiviruses are large double-stranded DNA viruses related to baculoviruses known to be endogenized in the genomes of certain parasitic wasp species. These wasp-virus associations allow the production of viral particles or virus-like particles that ensure wasp parasitism success within lepidopteran hosts. is an ichneumonid wasp belonging to the Campopleginae subfamily that has endogenized nudivirus genes belonging to the genus to produce "virus-like particles" ( virus-like particles [VcVLPs]), which package proteic virulence factors. The main aim of this study was to determine whether alphanudivirus gene functions have been conserved following endogenization. The expression dynamics of alphanudivirus genes was monitored by a high throughput transcriptional approach, and the functional role of and genes predicted to encode viral RNA polymerase components was investigated by RNA interference. As described for baculovirus infections and for endogenized nudivirus genes in braconid wasp species producing bracoviruses, a transcriptional cascade involving early and late expressed alphanudivirus genes could be observed. The expression of and was also shown to be required for the expression of alphanudivirus late genes allowing correct particle formation. Together with previous literature, the results show that endogenization of nudiviruses in parasitoid wasps has repeatedly led to the conservation of the viral RNA polymerase function, allowing the production of viruses or viral-like particles that differ in composition but enable wasp parasitic success. This study shows that endogenization of a nudivirus genome in a Campopleginae parasitoid wasp has led to the conservation, as for endogenized nudiviruses in braconid parasitoid wasps, of the viral RNA polymerase function, required for the transcription of genes encoding viral particles involved in wasp parasitism success. We also showed for the first time that RNA interference (RNAi) can be successfully used to downregulate gene expression in this species, a model in behavioral ecology. This opens the opportunity to investigate the function of genes involved in other traits important for parasitism success, such as reproductive strategies and host choice. Fundamental data acquired on gene function in are likely to be transferable to other parasitoid wasp species used in biological control programs. This study also renders possible the investigation of other nudivirus gene functions, for which little data are available.
Nudiviruses 是一类与杆状病毒有关的大型双链 DNA 病毒，已知它们在某些寄生蜂物种的基因组中内源性化。这些蜂病毒的关联允许产生病毒粒子或类病毒粒子，从而确保在鳞翅目宿主中寄生蜂的成功寄生。 是一种属于 Campopleginae 亚科的姬蜂，它已经内源性化了 nudivirus 基因，属于 属，以产生“类病毒粒子”（virus-like particles [VcVLPs]），这些粒子包装蛋白毒力因子。本研究的主要目的是确定 nudivirus 基因的功能在内源性化后是否得到了保守。通过高通量转录方法监测 alphanudivirus 基因的表达动态，并通过 RNA 干扰研究预测编码病毒 RNA 聚合酶成分的 和 基因的功能作用。正如杆状病毒感染和产生 bracoviruses 的 braconid 寄生蜂物种中的内源性 nudivirus 基因所描述的那样，可以观察到涉及早期和晚期表达的 alphanudivirus 基因的转录级联。还表明 和 的表达对于 alphanudivirus 晚期基因的表达是必需的，这允许正确的颗粒形成。结合以前的文献，结果表明，在寄生蜂中 nudivirus 的内源性化反复导致病毒 RNA 聚合酶功能的保守，从而产生在组成上不同但能使寄生蜂成功寄生的病毒或类病毒粒子。本研究表明，在 Campopleginae 寄生蜂中 nudivirus 基因组的内源性化导致了与 braconid 寄生蜂中内源性 nudiviruses 相同的病毒 RNA 聚合酶功能的保守，该功能对于转录参与寄生蜂成功寄生的病毒粒子编码基因是必需的。我们还首次表明，RNA 干扰（RNAi）可以成功用于下调该物种的基因表达，这是行为生态学中的一个模型。这为研究与寄生成功相关的其他重要性状（如生殖策略和宿主选择）的基因功能开辟了机会。在 中获得的关于基因功能的基础数据可能适用于其他用于生物防治计划的寄生蜂物种。这项研究还使得调查其他 nudivirus 基因功能成为可能，而对于这些基因功能，我们知之甚少。
