Wulff Juan P, Laminack Rachel K, Scott Maxwell J
Entomology and Plant Pathology, NCSU, Raleigh, NC, USA.
Parasit Vectors. 2025 Jul 9;18(1):270. doi: 10.1186/s13071-025-06804-0.
The blowfly Lucilia cuprina is a destructive parasite of sheep that causes flystrike or myiasis. Larvae consume the animal's living flesh, producing large wounds that can lead to death. The main aim of this study was to identify genes that may play important roles in the behavior and physiology of L. cuprina larvae.
An RNA-Seq analysis of RNA from whole larvae at different developmental stages and third-instar head and gut tissues was used to identify sensory receptors and other genes relevant to the physiology of L. cuprina larvae. In addition, CRISPR/Cas9 gene editing was used to obtain a loss-of-function mutation for the L. cuprina odorant coreceptor gene (LcupOrco). The response of mutant larvae and adult females to fresh and rotten meat at different temperatures was evaluated.
The RNA-Seq analysis suggested that odorant (OR), gustatory, ionotropic, and Pickpocket receptors may not play a central role in the L. cuprina larval sensory signaling and digestive systems. Rather, ATP-binding cassettes (ABCs) were highly enriched in head and gut RNA, and odorant-binding proteins (OBPs) only in the head. To confirm that ORs are not essential for larval detection of rotten beef, diet-choice assays were performed including larvae and adults homozygous for a null mutation in LcupOrco. While the attraction of adult females to rotten beef was disrupted, LcupOrco mutant larvae showed no change in diet preference.
The expression pattern of the ABC and OBP gene families suggests a central role in the sensory system of the L. cuprina larva for these receptors. Behavioral assays showed that ORs are essential for the adult female response to rotten beef, but not for larval behavior. These findings are consistent with high levels of expression of LcupOrco in the adult female antenna but very low expression in larvae.
绿蝇 Lucilia cuprina 是绵羊的一种具有破坏性的寄生虫，会导致蝇蛆病或羊蝇蛆症。幼虫会啃食动物的活体组织，造成大的伤口，可能导致死亡。本研究的主要目的是鉴定可能在绿蝇 Lucilia cuprina 幼虫的行为和生理中起重要作用的基因。
对不同发育阶段的整个幼虫以及三龄幼虫的头部和肠道组织的 RNA 进行 RNA 测序分析，以鉴定与绿蝇 Lucilia cuprina 幼虫生理相关的感觉受体和其他基因。此外，使用 CRISPR/Cas9 基因编辑技术获得绿蝇 Lucilia cuprina 气味共受体基因（LcupOrco）的功能缺失突变体。评估了突变幼虫和成年雌性在不同温度下对新鲜和腐烂肉类的反应。
RNA 测序分析表明，气味受体（OR）、味觉受体、离子型受体和 Pickpocket 受体可能在绿蝇 Lucilia cuprina 幼虫的感觉信号传导和消化系统中不发挥核心作用。相反，ATP 结合盒（ABC）在头部和肠道 RNA 中高度富集，而气味结合蛋白（OBP）仅在头部中存在。为了证实 OR 对幼虫检测腐烂牛肉不是必需的，进行了饮食选择试验，其中包括 LcupOrco 基因纯合缺失突变的幼虫和成虫。虽然成年雌性对腐烂牛肉的吸引力受到破坏，但 LcupOrco 突变体幼虫的饮食偏好没有变化。
ABC 和 OBP 基因家族的表达模式表明这些受体在绿蝇 Lucilia cuprina 幼虫的感觉系统中起核心作用。行为试验表明，OR 对成年雌性对腐烂牛肉的反应至关重要，但对幼虫行为并非如此。这些发现与 LcupOrco 在成年雌性触角中高表达但在幼虫中极低表达一致。
