An Aedes aegypti-associated fungus increases susceptibility to dengue virus by modulating gut trypsin activity

Abstract

Transmission of dengue virus (DENV) requires successful completion of the infection cycle in the <i>Aedes aegypti</i> vector, which is initiated in the midgut tissue after ingestion of an infectious blood meal. While certain <i>Ae. aegypti</i> midgut-associated bacteria influence virus infection, little is known about the midgut-associated fungi (mycobiota), and how its members might influence susceptibility to DENV infection. We show that a <i>Talaromyces</i> (<i>Tsp_PR</i>) fungus, isolated from field-caught <i>Ae. aegypti,</i> render the mosquito more permissive to DENV infection. This modulation is attributed to a profound down-regulation of digestive enzyme genes and trypsin activity, upon exposure to <i>Tsp_PR</i>-secreted factors. In conclusion, we show for the first time that a natural mosquito gut-associated fungus can alter <i>Ae. aegypti</i> physiology in a way that facilitates pathogen infection.