Insect pathogenic fungus interacts with the gut microbiota to accelerate mosquito mortality

Abstract

Significance As insecticide resistance is rapidly spreading, alternative tools for mosquito control are urgently needed. Beauveria bassiana is equally effective at killing insecticide-resistant and insecticide-susceptible mosquitoes. Better understanding of fungus–mosquito interactions is critical for improvement of its efficacy. Here we discover a contributory role for the gut microbiota in promoting fungal killing of mosquitoes via down-regulation of antimicrobial peptides and dual oxidase in the midgut. Fungal infection results in dysbiosis of mosquito gut microbiota by significantly increasing gut bacterial loads and decreasing bacterial diversity. In particular, fungal infection causes overgrowth and translocation of the opportunistic pathogen Serratia marcescens from the gut to the hemocoel, thus promoting mosquito death. Our study may lead to new strategies for biological control of mosquitoes.