Data from: Combining RNA-seq and proteomic profiling to identify seminal fluid proteins in the migratory grasshopper Melanoplus sanguinipes (F)

Background: Seminal fluid proteins control many aspects of fertilization and in turn, they play a key role in post-mating sexual selection and possibly reproductive isolation. Because effective proteome profiling relies on the availability of high-quality DNA reference databases, our knowledge of these proteins is still largely limited to model organisms with ample genetic resources. New advances in sequencing technology allow for the rapid characterization of transcriptomes at low cost. By combining high throughput RNA-seq and shotgun proteomic profiling, we have characterized the seminal fluid proteins secreted by the primary male accessory gland of the migratory grasshopper (Melanoplus sanguinipes), one of the main agricultural pests in central North America. Results: Using RNA sequencing, we characterized the transcripts of ~ 8,100 genes expressed in the long hyaline tubules (LHT) of the accessory glands. Proteomic profiling identified 353 proteins expressed in the long hyaline tubules (LHT). Of special interest are seminal fluid proteins (SFPs), such as EJAC-SP, ACE and prostaglandin synthetases, which are known to regulate female oviposition in insects. Conclusions: Our study provides new insights into the proteomic components of male ejaculate in Orthopterans, and highlights several important patterns. First, the presence of proteins that lack predicted classical secretory tags in accessory gland proteomes is common in male accessory glands. Second, the products of a few highly expressed genes dominate the accessory gland secretions. Third, accessory gland transcriptomes are enriched for novel transcripts. Fourth, there is conservation of SFPs’ functional classes across distantly related taxonomic groups with very different life histories, mating systems and sperm transferring mechanisms. The identified SFPs may serve as targets of future efforts to develop species- specific genetic control strategies.

研究背景：精液蛋白（seminal fluid proteins, SFPs）调控受精过程的诸多环节，进而在交配后性选择乃至生殖隔离中发挥关键作用。由于高效的蛋白质组分析依赖于高质量DNA参考数据库的支撑，目前学界对这类蛋白的认知大多局限于具备充足遗传资源的模式生物。测序技术的新近进展使得我们能够以低成本快速完成转录组表征。本研究结合高通量RNA测序与鸟枪法蛋白质组分析，对作为北美中部主要农业害虫之一的迁飞蝗虫（Melanoplus sanguinipes）的雄性副腺主腺体所分泌的精液蛋白进行了系统表征。

研究结果：本研究通过RNA测序，对副腺长透明小管（long hyaline tubules, LHT）中表达的约8100个基因的转录本完成了表征。蛋白质组分析共鉴定出长透明小管（LHT）中表达的353种蛋白。其中尤为值得关注的是SFPs，如EJAC-SP、ACE与前列腺素合成酶，这类蛋白已被证实可调控昆虫雌虫的产卵行为。

研究结论：本研究为直翅目（Orthopterans）昆虫雄性射精液的蛋白质组组分提供了全新视角，并揭示了若干重要规律：其一，雄性副腺的蛋白质组中普遍存在缺乏预测性经典分泌信号肽的蛋白；其二，副腺分泌物主要由少数高表达基因的产物构成；其三，副腺转录组富含全新转录本；其四，尽管不同分类类群亲缘关系较远，且生活史、交配系统与精子传递机制差异显著，其SFPs的功能类群仍具有保守性。本研究鉴定出的SFPs可作为未来开发物种特异性遗传防控策略的潜在靶点。