Stability of the Virome in Lab- and Field-Collected Aedes albopictus Mosquitoes across Different Developmental Stages and Possible Core Viruses in the Publicly Available Virome Data of <i>Aedes</i> Mosquitoes

Abstract

<i>Aedes</i> mosquitoes can efficiently transmit many pathogenic arboviruses, placing a great burden on public health worldwide. In addition, they also carry a number of insect-specific viruses (ISVs), and it was recently suggested that some of these ISVs might form a stable species-specific "core virome" in mosquito populations. However, little is known about such a core virome in laboratory colonies and if it is present across different developmental stages. In this study, we compared the viromes in eggs, larvae, pupae, and adults of <i>Aedes albopictus</i> mosquitoes collected from a lab colony and compared each to the virome of different developmental stages collected in the field. The virome in lab-derived <i>A. albopictus</i> was very stable across all stages, consistent with a vertical transmission route of these viruses, and formed a possible "vertically transmitted core virome." The different stages of field-collected <i>A. albopictus</i> mosquitoes also contained this stable vertically transmitted core virome, as well as another set of viruses (e.g., viruses distantly related to Guadeloupe mosquito virus, Hubei virga-like virus 2, and Sarawak virus) shared by mosquitoes across different stages, which might represent an "environment-derived core virome." To further study this core set of ISVs, we screened 48 publicly available SRA viral metagenomic data sets of mosquitoes belonging to the genus <i>Aedes</i>, showing that some of the identified ISVs were identified in the majority of SRAs and providing further evidence supporting the core-virome concept.<b>IMPORTANCE</b> Our study revealed that the virome was very stable across all developmental stages of both lab-derived and field-collected <i>Aedes albopictus</i> The data representing the core virome in lab <i>A. albopictus</i> proved the vertical transmission route of these viruses, forming a "vertically transmitted core virome." Field mosquitoes also contained this stable vertically transmitted core virome as well as additional viruses, which probably represented "environment-derived core virome" and which therefore were less stable over time and geography. By further screening publicly available SRA viral metagenomic data sets from mosquitoes belonging to the genus <i>Aedes</i>, some of the identified core ISVs were shown to be present in the majority of SRAs, such as Phasi Charoen-like phasivirus and Guadeloupe mosquito virus. How these core ISVs influence the biology of the mosquito host and arbovirus infection and evolution deserves to be further explored.