DOKPOMIWA Houeffa Adeline Tatiana

Curriculum :
M.Sc Molecular Biology and Genetic Engineering

ACE affiliate :
CEA/ITECH-MTV

Thesis title :
Molecular immunity to co-infection of the bacterium Wolbachia and the entomopathogenic fungus Metarhizium pingshaense in Aedes aegypti as part of the fight against dengue fever.

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Project title:
Molecular immunity of co-infection of Wolbachia bacteria and Metarhizium pingshaense entomopathogenic fungus in Aedes aegypti for dengue control.

Topic summary:

To date, the fight against dengue relies essentially on vector control, which is already threatened by the resistance of vectors to insecticides, necessitating the development of biological approaches. The involvement of Wolbachia and entomopathogenic fungi in mosquito population control strategies is a real advantage for biological vector control. However, little is known about the molecular immunity of mosquitoes artificially infected with Wolbachia after fungal infection. The aim of this work was therefore to study the immune basis of the protection conferred to Aedes aegypti by Wolbachia strains against infection by Metarhizium pingshaense.

Summary of results:

Our results revealed that while strong protection against infection was observed in mosquitoes transfected with Wolbachia wAu and moderate susceptibility in mosquitoes transfected with Wolbachia wAlbB, wild-type mosquitoes showed increased susceptibility to fungal infection. Furthermore, our results suggest that fungal infection increases Wolbachia density in mosquitoes around day 5 post-infection and that this was dependent on Wolbachia strain. Finally, we found overexpression of the immune factors REL1, MyD88, REL2, IMD and the immune effectors DEFA, DEFC and TEP22 in Wolbachia-transfected mosquitoes (wAlbB and wAu). These results indicate that the Toll and IMD pathways are involved in the antifungal response of mosquitoes, and that the presence of Wolbachia in mosquitoes enhances the antifungal response. Similarly, the results suggest that Wolbachia wAu confers a better immune response to fungal infection than Wolbachia wAlbB.