Mosquitoes are prolific vectors of human pathogens, therefore a clear and accurate understanding of the organization of their antimicrobial defenses is crucial for informing the development of transmission control strategies. The canonical infection response in insects, as described in the insect model Drosophila melanogaster, is pathogen type-dependent, with distinct stereotypical responses to Gram-negative bacteria and Gram-positive bacteria/fungi mediated by the activation of the Imd and Toll pathways, respectively. To determine whether this pathogen-specific discrimination is shared by mosquitoes, we used RNAseq to capture the genome-wide transcriptional response of Aedes aegypti and Anopheles gambiae (s.l.) to systemic infection with Gram-negative bacteria, Gram-positive bacteria, yeasts, and filamentous fungi, as well as challenge with heat-killed Gram-negative, Gram-positive, and fungal pathogens. From the resulting data, we found that Ae. aegypti and An. gambiae both mount a core response to all categories of infection, and this response is highly conserved between the two species with respect to both function and orthology. When we compared the transcriptomes of mosquitoes infected with different types of bacteria, we observed that the intensity of the transcriptional response was correlated with both the virulence and growth rate of the infecting pathogen. Exhaustive comparisons of the transcriptomes of Gram-negative-challenged versus Gram-positive-challenged mosquitoes yielded no difference in either species. In Ae. aegypti, however, we identified transcriptional signatures specific to bacterial infection and to fungal infection. The bacterial infection response was dominated by the expression of defensins and cecropins, while the fungal infection response included the disproportionate upregulation of an uncharacterized family of glycine-rich proteins. These signatures were also observed in Ae. aegypti challenged with heat-killed bacteria and fungi, indicating that this species can discriminate between molecular patterns that are specific to bacteria and to fungi.

中文翻译：

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蚊子的转录反应区分真菌和细菌，但不能区分革兰氏菌类型

蚊子是人类病原体的多产载体，因此清晰准确地了解其抗菌防御的组织对于制定传播控制策略至关重要。正如昆虫模型果蝇中所描述的，昆虫中的典型感染反应是病原体类型依赖性的，对革兰氏阴性细菌和革兰氏阳性细菌/真菌分别具有通过激活 Imd 和 Toll 途径介导的独特的典型反应。为了确定蚊子是否也存在这种病原体特异性歧视，我们使用 RNAseq 捕获了埃及伊蚊和冈比亚按蚊 (sl) 对革兰氏阴性菌、革兰氏阳性菌、酵母菌和疟原虫全身感染的全基因组转录反应。丝状真菌，以及热灭活的革兰氏阴性、革兰氏阳性和真菌病原体的攻击。从结果数据中，我们发现 Ae.埃及伊蚊和安.冈比亚人和冈比亚人都对所有类别的感染都有核心反应，并且这种反应在功能和直系学方面在两个物种之间高度保守。当我们比较感染不同类型细菌的蚊子的转录组时，我们观察到转录反应的强度与感染病原体的毒力和生长速度相关。对革兰氏阴性攻击与革兰氏阳性攻击的蚊子的转录组进行详尽比较，没有发现这两个物种存在差异。在艾。然而，我们鉴定了埃及伊蚊细菌感染和真菌感染特有的转录特征。细菌感染反应主要是防御素和天蚕素的表达，而真菌感染反应包括未表征的富含甘氨酸的蛋白质家族的不成比例上调。在 Ae 中也观察到了这些特征。埃及伊蚊受到热灭活细菌和真菌的挑战，表明该物种可以区分细菌和真菌特有的分子模式。