A transcriptomic atlas of Aedes aegypti reveals detailed functional organization of major body parts and gut regional specializations in sugar-fed and blood-fed adult females

Abstract

Mosquito vectors transmit numerous pathogens, but large gaps remain in our understanding of their physiology. To facilitate future explorations of mosquito biology, with specific attention to the major vector Aedes aegypti, we have created Aegypti-Atlas (http://aegyptiatlas.buchonlab.com/), an online resource hosting RNAseq profiles of Ae. Aegypti body parts (head, thorax, abdomen, gut, Malpighian tubules, and ovaries), gut regions (crop, proventriculus, anterior and posterior midgut, and hindgut), and a time course of blood meal digestion in the gut. Using Aegypti-Atlas, we provide new insights into the regionalization of gut function, blood feeding response, and immune defenses. We find that the anterior and posterior regions of the mosquito midgut possess clearly delineated digestive specializations which are preserved in the blood-fed state. Blood feeding initiates the sequential transcriptional induction and repression/depletion of multiple cohorts of peptidases throughout blood meal digestion. With respect to defense, immune signaling components, but not recognition or effector molecules, show enrichment in ovaries. Basal expression of antimicrobial peptides is dominated by two genes, holotricin and gambicin, that are expressed in the carcass and the digestive tissues, respectively, in a near mutually exclusive manner. In the midgut, gambicin and other immune effector genes are almost exclusively expressed in the anterior regions, while the posterior midgut exhibits the hallmarks of immune tolerance. Finally, in a cross-species comparison between the midguts of Ae. aegypti and Anopheles gambiae, we observe that regional digestive and immune specializations are closely conserved, indicating that our data may yield inferences that are broadly relevant to multiple mosquito vector species. We further demonstrate that the expression of orthologous genes is highly correlated, with the exception of a species signature comprising a small number of highly/disparately expressed genes. With this work, we show the potential of Aegypti-Atlas to unlock a more complete understanding of mosquito biology.