The Maternally Inheritable AlbB Induces Refractoriness to in .

The endosymbiont AlbB induces refractoriness to in , the primary mosquito vector of human malaria in the Middle East and South Asia. However, it remains unknown whether such refractoriness can be extended to other malaria species. In particular, it was reported that under very specific conditions, AlbB can enhance infection in some hosts. Here, we measured the impact of AlbB on the rodent malaria parasite in by comparing the load of oocysts and sporozoites in midguts and salivary glands, respectively, between AlbB-infected and -uninfected mosquitoes. To investigate whether AlbB modulated mosquito immune defense against parasites, we compared the expression of the immune genes, which were previously reported to involve in antimalarial response, in both midguts and the remaining carcass tissues of mosquitoes. The stable association of AlbB with resulted in reduction of parasites by more than half at the oocyst stage, and up to 91.8% at the sporzoite stage. The anti- immune genes, including , , Toll pathway gene and the effector , were induced by AlbB in different mosquito body tissues. These findings suggest that immune priming is a potential cause of AlbB-mediated antimalarial response in . More importantly, no evidence was found for any enhancement of infection in stably infected with AlbB. We discuss these findings with possible implementations of for malaria control in disease endemic areas.