Genetic specificity and potential for local adaptation between dengue viruses and mosquito vectors

Louis Lambrechts (1, 2) , Christine Chevillon (3, 1) , Rebecca G Albright (2) , Butsaya Thaisomboonsuk (4) , Jason H Richardson (5) , Richard G Jarman (4) , Thomas W Scott (2)

1 GEMI - Génétique et évolution des maladies infectieuses
2 UC Davis - University of California [Davis]
3 MIVEGEC-EVCO - Evolution of host-microbe communities
4 Department of Virology
5 AFRIMS - Armed Forces Research Institute of Medical Sciences [Bangkok]

Background: Several observations support the hypothesis that vector-driven selection plays an important role in shaping dengue virus (DENV) genetic diversity. Clustering of DENV genetic diversity at a particular location may reflect underlying genetic structure of vector populations, which combined with specific vector genotype × virus genotype (G × G) interactions may promote adaptation of viral lineages to local mosquito vector genotypes. Although spatial structure of vector polymorphism at neutral genetic loci is well-documented, existence of G × G interactions between mosquito and virus genotypes has not been formally demonstrated in natural populations. Here we measure G × G interactions in a system representative of a natural situation in Thailand by challenging three isofemale families from field-derived Aedes aegypti with three contemporaneous low-passage isolates of DENV-1.Results: Among indices of vector competence examined, the proportion of mosquitoes with a midgut infection, viral RNA concentration in the body, and quantity of virus disseminated to the head/legs (but not the proportion of infected mosquitoes with a disseminated infection) strongly depended on the specific combinations of isofemale families and viral isolates, demonstrating significant G × G interactions.Conclusion: Evidence for genetic specificity of interactions in our simple experimental design indicates that vector competence of Ae. aegypti for DENV is likely governed to a large extent by G × G interactions in genetically diverse, natural populations. This result challenges the general relevance of conclusions from laboratory systems that consist of a single combination of mosquito and DENV genotypes. Combined with earlier evidence for fine-scale genetic structure of natural Ae. aegypti populations, our finding indicates that the necessary conditions for local DENV adaptation to mosquito vectors are met.

Domaines: Virologie; Interactions entre organismes; Evolution [q-bio.PE]

Louis Lambrechts, Christine Chevillon, Rebecca G Albright, Butsaya Thaisomboonsuk, Jason H Richardson, et al.. Genetic specificity and potential for local adaptation between dengue viruses and mosquito vectors. BMC Evolutionary Biology, 2009, 9, pp.160. ⟨10.1186/1471-2148-9-160⟩. ⟨hal-02152278⟩