Wolbachia transinfections in Culex quinquefasciatus generate cytoplasmic incompatibility

Abstract

Culex quinquefasciatus is an important mosquito vector of a number of viral and protozoan pathogens of humans and animals, and naturally carries the endosymbiont Wolbachia pipientis, strain wPip. Wolbachia are used in two distinct vector control strategies: firstly, population suppression caused by mating incompatibilities between mass‐released transinfected males and wild females; and secondly, the spread of pathogen transmission‐blocking strains through populations. Using embryonic microinjection, two novel Wolbachia transinfections were generated in C. quinquefasciatus using strains native to the mosquito Aedes albopictus: a wAlbB single infection, and a wPip plus wAlbA superinfection. The wAlbB infection showed full bidirectional cytoplasmic incompatibility (CI) with wild‐type C. quinquefasciatus in reciprocal crosses. The wPipwAlbA superinfection showed complete unidirectional CI, and therefore population invasion potential. Whereas the wAlbB strain showed comparatively low overall densities, similar to the native wPip, the wPipwAlbA superinfection reached over 400‐fold higher densities in the salivary glands compared to the native wPip, suggesting it may be a candidate for pathogen transmission blocking.

WolbachiastrainwAlbB maintains high density and dengue inhibition following introduction into a field population ofAedes aegypti

“…Furthermore, selection for reduced wMelPop densities in D. simulans may be particularly rapid as it is a native Wolbachia host; existing host factors capable of suppressing native strains may be active against novel associations, although these factors may require some adaptative optimization against divergent Wolbachia strains. When wAlbB was transferred into Culex quinquefasciatus, for example, it showed a limited somatic tissue distribution similar to the native wPip strain-with which it is closely related-while the more distantly related wAlbA strain which was also transferred reached high somatic densities [30]. The low fitness costs associated with wAlbB and the absence of native Wolbachia in Ae.…”

Living in the endosymbiotic world of Wolbachia: A centennial review

“…Thus, release of Wolbachia-infected males suppress the mosquito population size in the field (Figure 5b) as has been achieved in China (wPip, wAlbB and wAlbB in A. aegypti), Italy, Singapore and America (wPip in A. albopictus and wAlbB in A. aegypti) (Caputo et al, 2020;Mains et al, 2016;Puggioli et al, 2016;Zheng et al, 2019). Work is in progress to expand IIT to control other vectors and pests, including the fruit pest Ceratitis capitata (Kyritsis et al, 2019) and protozoan vector C. quinquefasciatus (Ant et al, 2020).…”

Symbiont-mediated cytoplasmic incompatibility: What have we learned in 50 years?

“…Two CI-based vector control strategies are deployed worldwide. First, the incompatible insect technique (IIT), also known as population suppression, aims to reduce the population size of disease vectors through release of CI-inducing male insects ( Figure 2A ; Ant et al, 2020 ; Caputo et al, 2020 ; Chambers et al, 2011 ; Crawford et al, 2020 ; Fresno, 2018 ; Kyritsis et al, 2019 ; Laven, 1967 ; Mains et al, 2019 ; Mains et al, 2016 ; O'Connor et al, 2012 ; Puggioli et al, 2016 ; Zheng et al, 2019a ). Conversely, the population replacement strategy (PRS) does not reduce population sizes, but instead it aims to convert a native population that transmits arboviruses to humans with one that has reduced vectoral capacity ( Figure 2B ; Caragata et al, 2016 ; Hoffmann et al, 2011 ; Moreira et al, 2009 ; O'Neill, 2018 ; Tantowijoyo et al, 2020 ; Teixeira et al, 2008 ; van den Hurk et al, 2012 ).…”