BACKGROUND Mosquitoes are the most important invertebrate viral vectors in humans and harbor a high diversity of understudied viruses, which has been shown in many mosquito virome studies in recent years. These studies generally performed metagenomics sequencing on pools of mosquitoes, without assessment of the viral diversity in individual mosquitoes. To address this issue, we applied our optimized viral metagenomics protocol (NetoVIR) to compare the virome of single and pooled Aedes aegypti and Culex quinquefasciatus mosquitoes collected from different locations in Guadeloupe, in 2016 and 2017. RESULTS The total read number and viral reads proportion of samples containing a single mosquito have no significant difference compared with those of pools containing five mosquitoes, which proved the feasibility of using single mosquito for viral metagenomics. A comparative analysis of the virome revealed a higher abundance and more diverse eukaryotic virome in Aedes aegypti, whereas Culex quinquefasciatus harbors a richer and more diverse phageome. The majority of the identified eukaryotic viruses were mosquito-species specific. We further characterized the genomes of 11 novel eukaryotic viruses. Furthermore, qRT-PCR analyses of the six most abundant eukaryotic viruses indicated that the majority of individual mosquitoes were infected by several of the selected viruses with viral genome copies per mosquito ranging from 267 to 1.01 × 108 (median 7.5 × 106) for Ae. aegypti and 192 to 8.69 × 106 (median 4.87 × 104) for Cx. quinquefasciatus. Additionally, in Cx. quinquefasciatus, a number of phage contigs co-occurred with several marker genes of Wolbachia sp. strain wPip. CONCLUSIONS We firstly demonstrate the feasibility to use single mosquito for viral metagenomics, which can provide much more precise virome profiles of mosquito populations. Interspecific comparisons show striking differences in abundance and diversity between the viromes of Ae. aegypti and Cx. quinquefasciatus. Those two mosquito species seem to have their own relatively stable "core eukaryotic virome", which might have important implications for the competence to transmit important medically relevant arboviruses. The presence of Wolbachia in Cx. quinquefasciatus might explain (1) the lower overall viral load compared to Ae. aegypti, (2) the identification of multiple unknown phage contigs, and (3) the difference in competence for important human pathogens. How these viruses, phages, and bacteria influence the physiology and vector competence of mosquito hosts warrants further research.

中文翻译：

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使用单个蚊子病毒宏基因组学，在瓜德罗普岛不同蚊种中稳定的独特核心真核生物病毒。

背景技术蚊子是人类中最重要的无脊椎动物病毒载体，并具有高度被研究的病毒多样性，这在近年来的许多蚊子病毒学研究中已经显示出来。这些研究通常在蚊子池中进行宏基因组学测序，而没有评估单个蚊子的病毒多样性。为解决此问题，我们应用了优化的病毒宏基因组学方案（NetoVIR），比较了2016年和2017年从瓜德罗普岛不同地点收集的埃及埃及伊蚊和库蚊（Culex quinquefasciatus）蚊子的病毒情况。结果总阅读量和病毒阅读比例包含单个蚊子的样本与包含五个蚊子的样本池相比没有显着差异，这证明了使用单个蚊子进行病毒宏基因组学的可行性。对该病毒的比较分析显示埃及伊蚊具有更高的丰度和更多样化的真核病毒，而库克斯库克斯库库斯（Culex quinquefasciatus）则具有更丰富和更多样化的噬菌体。大多数鉴定出的真核病毒是蚊种特异性的。我们进一步表征了11种新型真核病毒的基因组。此外，对六种最丰富的真核病毒的qRT-PCR分析表明，大多数单个蚊子感染了几种选定的病毒，每个蚊子的病毒基因组拷贝数为267至1.01×108（中位数为7.5×106）。aegypti和Cx的192至8.69×106（中位数4.87×104）。quinquefasciatus。此外，在Cx中。quinquefasciatus，许多噬菌体重叠群与Wolbachia sp。的几个标记基因共存。应变wPip。结论我们首先证明了使用单一蚊子进行病毒宏基因组学的可行性，它可以提供蚊子种群更精确的病毒谱。种间比较显示，Ae病毒之间的丰度和多样性存在显着差异。埃及和Cx。quinquefasciatus。这两种蚊子似乎具有自己相对稳定的“核心真核生物病毒”，这可能对传播重要的医学相关虫媒病毒的能力具有重要意义。Cx中存在Wolbachia。quinquefasciatus可能解释了（1）与Ae相比，总的病毒载量较低。aegypti，（2）鉴定多个未知噬菌体重叠群，（3）重要人类病原体能力的差异。这些病毒，噬菌体和细菌如何影响蚊子宿主的生理和媒介能力值得进一步研究。