The best sugar in town for malaria transmission

Abstract

Anopheles mosquitoes feed on plant nectars as their main source of sugar. Wang et al. show that Asaia bacteria proliferate in the midgut of mosquitoes that feed on glucose or trehalose. Asaia increases the lumenal pH by downregulating mosquito vacuolar ATPase expression, therefore increasing Plasmodium gametogenesis and vector competence.

Keywords: Anopheles; Plasmodium; glucose; microbiome; vectorial capacity.

Figure 1.. The mosquito’s sugar diet shapes vector competence during Plasmodium infection.

Upper panel. Glucose and trehalose promote Plasmodium berghei infectivity. Mosquitoes feeding on a diet rich in glucose or trehalose sustain the proliferation of Asaia bogorensis in the midgut. Wang et al. [3] propose that glucose or trehalose catabolized by A. bogorensis triggers a downregulation of mosquito V-ATPase by a yet unknown mechanism. Downregulation of the V-ATPase proton transporter elevates midgut lumenal pH which, in turn, promotes gametogenesis by stimulating exflagellation. These interactions increase the number of oocysts in the midgut, and therefore, vector competence. Lower panel. Mosquitoes feeding on sucrose reduce the abundance of A. bogorensis, thus lowering sugar metabolism in the mosquito’s lumen. Consequently, this triggers the upregulation of the mosquito’s V-ATPase and the acidification of lumenal pH, therefore hindering Plasmodium gametogenesis and vector competence.