Functional studies of candidate genes involved in food preference in Calliphoridae (Diptera) using the model species Drosophila melanogaster

Abstract

Cochliomyia hominivorax is a parasite of economic and veterinary importance. The losses caused by this species impact mostly cattle breeding farms and domestic animals. This plague was first eradicated in the U.S. using the sterilized insect technique (SIT). Despite of this great effort, this species still occurs in parts of Central and the entire South America. In Brazil, organophosphate insecticides are widely used to prevent and treat these infestations resulting in the selection of resistant strains. One way to improve this pest management is to study the parasitic behavior of Co. hominivorax. Our research group initiated studies to understand the genetic basis of obligate parasitism in calliphorids using gene expression data in a phylogenetic context. Species of Calliphoridae have contrasting feeding habits facilitating the search for extreme differences within closely related species. We have recently used RNA-seq data to find differently expressed genes between different feeding habits and fast evolving coding regions in the parasitic species, Co. hominivorax. This approach provided us a set of candidate genes that might be involved in food preference. Thus, the main goal of this project is to understand the involvement of three candidate genes (Mvl, Ir87a and CG7142) in feeding habit. To achieve this objective, we will use the CRISPR-Cas9 system to insert Co. hominivorax genes in Drosophila melanogaster and test mutants across different behavior assays. We expect that the results obtained during this project will help elucidate the underlying genes involved in obligate parasitism in calliphorids.