The genome of the brackish-water malaria vector Anopheles aquasalis

Abstract

Anopheles aquasalis is a primary malaria vector in coastal South America that grows in brackish waters of mangroves. Its importance has increased in recent years as it has been established as a model for parasite-vector studies for non-model Plasmodium species, such as P. yoelli. In this study, we present the complete genome of An. aquasalis and offer some insights into evolution and physiology. With a 162Mb and 12,446 coding proteins, the An. aquasalis genome is similar in size and gene content as other neotropical anophelines. 1,038 single-copy orthologs are present in An. aquasalis and all Diptera and it was possible to infer that An. aquasalis diverged from An. darlingi (the main malaria vector in inland South America) nearly 14 million years ago (mya). Ion transport and metabolism proteins is one the major gene families in An. aquasalis with 660 genes. Amongst these genes, important gene families relevant for osmosis control (e.g., aquaporins, vacuolar-ATPases, Na+/K+-ATPases and carbonic anhydrases) were identified in one-to-one orthologs with other anophelines. Evolutionary analysis suggests that all osmotic regulation genes are under strong purifying selection. We also observed low copy number variation in immunity-related genes (for which all classical pathways were described) and insecticide resistance genes. This is the third genome of a neotropical anopheline published so far. The data provided by this study may offer candidate genes for further studies on parasite-vector interactions and for studies on how brackish water anophelines deals with high fluctuation in water salinity. Significance StatementThe brackish water mosquito Anopheles aquasalis is a primary malaria vector in coastal South America. Besides its peculiar ecological features (it is one of the few anopheline mosquitoes that survives high fluctuation of water salinity), An. aquasalis has gained relevance in recent years as a model for parasite-vector studies for non-model Plasmodium parasites. Still, the physiology and genetics of An. aquasalis are poorly understood. Here we present the genome of An. aquasalis with more than 12,000 annotated genes, offering insights in genome evolution, osmoregulation related, immunity, chemosensory and insecticide resistance genes. The data presented here will help to further advance the studies on An. aquasalis genetics and physiology to better understand parasite-vector interactions in non-model organisms.