Midgut fungal and bacterial microbiota of Aedes triseriatus and Aedes japonicus shift in response to La Crosse virus infection

Abstract

Understanding how midgut microbial communities of field-collected mosquitoes interact with pathogens is critical for controlling vector infection and disease. We used 16S rRNA and internal transcribed spacer sequencing to characterize the midgut bacterial and fungal communities of adult females of Aedes triseriatus and Aedes japonicus collected as pupae in tree holes, plastic bins and waste tires and their response to La Crosse virus (LACV) infection. For both mosquito species and across all habitat and virus treatments, a total of 62 bacterial operational taxonomic units (OTUs) from six phyla and 21 fungal OTUs from two phyla were identified. The majority of bacterial (92%) and fungal (71%) OTUs were shared between the mosquito species; however, several OTUs were unique to each species. Bacterial and fungal communities of individuals that took either infectious or noninfectious bloodmeals were less diverse and more homogeneous compared to those of newly emerged adults. Interestingly, LACV-infected A. triseriatus and A. japonicus had higher bacterial richness and lower fungal richness compared to individuals that took a noninfectious bloodmeal, suggesting that viral infection was associated with an increase in bacterial OTUs and a decrease in fungal OTUs. For both mosquito species, several OTUs were identified that had both high fidelity and specificity to mosquito midguts that were infected with LACV. Overall, these findings demonstrate that bacterial and fungal communities that reside in mosquito midguts respond to host diet and viral infection and could play a role in modulating vector susceptibility to LACV.

Comparative analysis of gut microbiota of mosquito communities in central Illinois

“…Similar individual variability in gut microbiota and the dominance of a few bacterial taxa in mosquito guts has been reported before [22]. These variations may result from individual variations in external and internal factors such as the gut physiological conditions, larval and adult diet, infection with parasites and pathogens, host aging [24, 26, 27, 38, 42], and host genetic background [43]. Our experimental design cannot decipher the contribution of these factors to the observed pattern of gut microbiota since adult mosquito samples were collected using the CDC light traps and we had no prior knowledge of the factors these mosquitoes were exposed to before collection.…”

“…These studies have revealed that the composition and diversity of gut microbiota can vary dramatically within [22] and between mosquito species [23] and are influenced by host diet [24], developmental stage [24], larval environment [25], and pathogen infection [26, 27]. As such, additional studies comparing the microbial communities of different mosquito species can further improve our understanding of mosquito microbiota and propel identification of specific microbes that may be harnessed for disease control.…”

Composition and functional roles of the gut microbiota in mosquitoes

“…Several bacteria identified as gut community members in mosquitoes have also been isolated and successfully cultured [13, 18, 22, 31, 50–53]. Unicellular eukaryotes identified as gut community members in different species of mosquitoes include fungi, algae, and Apicomplexa but thus far none of these organisms have been isolated from mosquitoes and cultured independently [43, 48, 54–57]. Sequence-based surveys also identify a number of viruses in mosquitoes [58, 59].…”

“…A large number of studies indicate that bacterial diversity differs substantially both between and within mosquito species as a function of collection location and other factors [14–18, 30, 42–46, 62, 63]. On a local scale, factors implicated in affecting community composition include habitat preferences of different mosquito species and larval feeding behavior [18, 30, 62].…”

Mosquito vector‐associated microbiota: Metabarcoding bacteria and eukaryotic symbionts across habitat types in Thailand endemic for dengue and other arthropod‐borne diseases

“…Recent improvements in the exploration of microscopic organisms through the use of metagenomic PCR (Hugenholtz, Goebel, & Pace, 1998; Liles, Manske, Bintrim, Handelsman, & Goodman, 2003) and next‐generation sequencing (Logares et al., 2012) have allowed more accurate and sensitive documentation of these organisms. Several studies have characterized and compared mosquito bacterial microbiota in natural habitats (Akorli et al., 2016; Buck et al., 2016; Gimonneau et al., 2014; Minard et al., 2012, 2014, 2015; Tchioffo et al., 2015; Yadav et al., 2015; Zouache et al., 2010) but few have characterized eukaryotes and in such cases have targeted fungi (Muturi, Bara, Rooney, & Hansen, 2016; Muturi, Ramirez, Rooney, & Dunlap, 2016; Steyn, Roets, & Botha, 2016). We document mosquito microbiota composition and diversity for vector species Aedes aegypti , Aedes albopictus , and Culex quinquefasciatus across ecologically distinct, yet geographically proximate, habitats in Thailand where many mosquito‐borne diseases circulate.…”