Using Sequencing-Based Approaches to Characterize Genetic Sexing Systems in Tephritid Fruit Flies

Tephritid fruit flies (Diptera: Tephritidae) are a major pest of worldwide economic importance. Their threat to high value agriculture is so extensive that area-wide integrated pest management programs (AW-IPM) are employed to prevent their long-term establishment in the mainland United States. An important component of these AW-IPM programs is the use of the sterile insect technique (SIT) by leveraging genetic sexing strains (GSS) that are established for these species. In order to have an effective SIT program, a genetic sexing strain (GSS) needs to be established for the species of interest, which facilitates cost-effective and rapid separation of female and male flies during mass-rearing, and release of male-only sterile flies. Our goal is to identify the genetic basis for the white pupae and temperature sensitive lethal traits in existing GSS, identify the causative mutations in genes causing phenotypic changes in these strains, and develop tools to transfer these traits to other economically important Tephritid species using targeted genome editing approaches. To address these objectives, we employed methodologies that bring together classical genetics with high-throughput sequencing techniques. Once putative causative mutations are identified, future research will employ comparative genomic analysis (orthology/synteny) to other Tephritid genomes, putative targets in those genomes will be identified to introduce the same GSS mutations into colony lines of those species. This will provide the foundation to developing GSS lines for important Tephritid pests which currently are not amenable to male only mass rearing for SIT.