State Key Laboratory of Pathogen and Biosecurity, Beijing Key Laboratory of Vector Borne and Natural Focus Infectious Disease, Beijing, 100071, China.
Parasit Vectors. 2022 Oct 1;15(1):353. doi: 10.1186/s13071-022-05482-6.
Both Culex quinquefasciatus and Cx. pipiens molestus are sibling species within Cx. pipiens complex. Even though they are hard to distinguish morphologically, they have different physiological behaviors. However, the molecular mechanisms underlying these differences remain poorly understood.
Transcriptome sequencing was conducted on antennae of two sibling species. The identification of the differentially expressed genes (DEGs) was performed by the software DESeq2. Database for Annotation, Visualization and Integrated Discovery was used to perform GO pathway enrichment analysis. The protein-protein interaction (PPI) network was constructed with Cytoscape software. The hub genes were screened by the CytoHubba plugin and Degree algorithms. The identified genes were verified by quantitative real-time PCR.
Most annotated transcripts (14,687/16,005) were expressed in both sibling species. Among 15 identified odorant-related DEGs, OBP10 was expressed 17.17 fold higher in Cx. pipiens molestus than Cx. quinquefasciatus. Eighteen resistance-related DEGs were identified, including 15 from CYP gene family and three from acetylcholinesterase, in which CYP4d1 was 86.59 fold more highly expressed in C. quinquefasciatus. Three reproductive DEGs were indentified with the expression from 5.01 to 6.55 fold. Among eight vision-related DEGs, retinoic acid receptor RXR-gamma in Cx. pipiens molestus group was more expressed with 214.08 fold. Among the 30 hub genes, there are 10 olfactory-related DEGs, 16 resistance-related DEGs, and four vision-related DEGs, with the highest score hub genes being OBP lush (6041148), CYP4C21 (6044704), and Rdh12 (6043932). The RT-qPCR results were consistent with the transcriptomic data with the correlation coefficient R = 0.78.
The study provided clues that antennae might play special roles in reproduction, drug resistance, and vision, not only the traditional olfactory function. OBP lush, CYP4C21, and Rdh12 may be key hints to the potential molecular mechanisms behind the two sibling species' biological differences.
致倦库蚊和白纹伊蚊是库蚊复合体中的两个近缘种。尽管它们在形态上难以区分，但它们具有不同的生理行为。然而，这些差异的分子机制仍知之甚少。
对两种近缘种的触角进行转录组测序。使用 DESeq2 软件鉴定差异表达基因（DEGs）。数据库 for Annotation, Visualization and Integrated Discovery 用于进行 GO 通路富集分析。使用 Cytoscape 软件构建蛋白质-蛋白质相互作用（PPI）网络。CytoHubba 插件和 Degree 算法筛选枢纽基因。通过定量实时 PCR 验证鉴定的基因。
大多数注释的转录本（14,687/16,005）在两种近缘种中均有表达。在鉴定出的 15 个气味相关 DEGs 中，白纹伊蚊的 OBP10 表达量比致倦库蚊高 17.17 倍。鉴定出 18 个抗性相关 DEGs，包括 CYP 基因家族的 15 个和乙酰胆碱酯酶的 3 个，其中 CYP4d1 在致倦库蚊中的表达量高 86.59 倍。鉴定出 3 个生殖相关 DEGs，表达水平为 5.01 至 6.55 倍。在 8 个视觉相关 DEGs 中，白纹伊蚊组的视黄酸受体 RXR-γ表达量高 214.08 倍。在 30 个枢纽基因中，有 10 个嗅觉相关 DEGs、16 个抗性相关 DEGs和 4 个视觉相关 DEGs，其中最高得分的枢纽基因是 OBP lush（6041148）、CYP4C21（6044704）和 Rdh12（6043932）。RT-qPCR 结果与转录组数据一致，相关系数 R=0.78。
该研究提供了线索，表明触角可能在生殖、药物抗性和视觉方面发挥特殊作用，而不仅仅是传统的嗅觉功能。OBP lush、CYP4C21 和 Rdh12 可能是这两个近缘种生物差异潜在分子机制的关键线索。
