Blood meal induced regulation of the chemosensory gene repertoire in the southern house mosquito

Abstract

BackgroundThe southern house mosquito, Culex quinquefasciatus, is one of the most prevalent vectors of lymphatic filariasis and flavivirus-induced encephalitis. Its vectorial capacity is directly affected by its reproductive feeding behaviors, such as host seeking, blood feeding, resting, and egg laying. In mosquitoes, these gonotrophic behaviors are odor-mediated and regulated following blood feeding. Immediately after a blood meal, female mosquitoes show reduced olfactory responsiveness and flight activity, as they enter a resting state. Insights into antennal chemosensory gene regulation at this time period can provide a foundation to identify targets involved in the state switch between host seeking and resting.ResultsThis study used quantitative gene expression analyses to explore blood meal induced regulation of chemosensory gene families in the antennae of 6 days post-emergence C. quinquefasciatus females. Improved annotations for multiple chemosensory gene families, and a quantitative differential gene expression analysis between host seeking and 24 h post- blood fed females of the same age, allowed for the detection of transcripts that potentially play a role in the switch from host seeking to resting, in C. quinquefasciatus. The expression profiles of chemosensory genes varied significantly between the two treatments.ConclusionsAnnotations for chemosensory gene repertoires in C. quinquefasciatus have been manually curated and corrected for 3’ exon choice and transcript length, through sequence and transcriptome analyses. The gene expression analyses identified various molecular components of the peripheral olfactory system in C. quinquefasciatus, including odorant receptors, ionotropic receptors, odorant binding proteins and chemosensory proteins, that are regulated in response to blood feeding, and could be critical for the behavioral switch from host seeking to resting. Functional characterization of these proteins in the future can identify targets essential for the females’ gonotrophic behaviors, and can be used to design novel vector control strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3779-2) contains supplementary material, which is available to authorized users.

Is Anopheles gambiae attraction to floral and human skin-based odours and their combination modulated by previous blood meal experience?

“…Shifts in blood host preference have been reported for mosquitoes [61,62]. Similarly, shifts in preference have been found depending on internal state, such as age, mating status, physiological status, and blood feeding status [63][64][65]. The modulation observed here, from oral to skin odour, also implies that following a blood meal mosquito may increasingly 'weigh' input from the IR circuitry, tuned to vertebrate hosts, in behavioural preference.…”

A synergistic transcriptional regulation of olfactory genes derives complex behavioral responses in the mosquito Anopheles culicifacies

“…It is well known that a circadian dependent modulation of olfactory responses significantly influences the biting behavior in Anopheline mosquito species (32). But the knowledge that how this olfactory derived modulation manages pre and post blood meal behavioral events is yet not well understood (24), (25) (27). Based on available literature and knowledge gaps, we argued that immediately after emergence adult female mosquitoes must undergoes two unique changes in their olfactory responses i.e.…”

“…We chose 30h PBM as a critical time when completion of blood meal digestion occurs in the midgut, which may have direct influence on the reactivation of the olfactory system ( Fig. S2) (24), (25), (34). For molecular and functional annotation, we assembled each transcriptomic database into contigs/Transcripts and compared against multiple molecular databases as described earlier (22).…”

“…Post blood meal mosquitoes need to enter into a new habitat favouring successful oviposition (23), (24). In fact, after blood meal acquisition, mosquitoes undergo two major behavioral switching events (i) search suitable site(s) for temporary resting and completion of blood meal digestion (~30hrs) which is necessary for egg maturation (48-72hrs); and (ii) find proper oviposition site for successful egg laying (25). After completion of egg laying event, the adult female mosquitoes regain hostseeking behavioral activities for a second blood meal to complete the next gonotrophic cycles (24), (26).…”

Blood Meal Induced Regulation of Gene Expression in the Maxillary Palps, a Chemosensory Organ of the Mosquito Aedes aegypti

“…The CEGMA gene set is a set of core eukaryotic genes (CEGs) identified as expressed in all eukaryotic animals and likely involved in essential cell processes (Parra et al, 2007). These genes were assessed to determine whether the depth of sequencing was sufficient to reliably identify expressed transcripts and to assess the stability of transcript abundance across libraries (Taparia et al, 2017). Ninetynine percent of the CEGs were found at detectable levels in the maxillary palps, indicating that the sequencing depth was sufficient to reliably identify gene expression ( Figure 1; Supplementary File 2).…”