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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Insect Behavior and Biocontrol Research » Research » Research Project #428668

Research Project: Conditional Lethal Tephritid Strains for Improved SIT and Genetic Stability

Location: Insect Behavior and Biocontrol Research

Project Number: 6036-22000-030-09-N
Project Type: Non-Funded Cooperative Agreement

Start Date: Jun 1, 2015
End Date: May 31, 2020

Objective:
The objective of this cooperative research project is to develop new transgenic strains for the fruit fly pests, Anastrepha (A.) ludens and Drosophila (D.) suzukii for Tet-off female-specific embryonic lethality for sexing and spermatocyte-specific lethality for male gonadal sterility. In combination, embryos reared on a Tet-free diet should result in male-only survivors that develop into sterile adults for release. Such sexing/sterility strains, however, will be subject to genetic breakdown due to lethal effect mutations, especially when mass-reared. To evaluate potential breakdown of a Tet-off lethality system, a D. suzukii uni-sex lethality strain will be reared under large-scale conditions to quantify lethal revertants that survive in the absence tetracycline. To prevent revertant survival a secondary temperature-dependent lethal system (DmDTS7) will be integrated into the Tet-off D. suzukii strain to assess survival under permissive and restrictive conditions. Assessing genetic reversion, and implementing a reversion suppression system in conditional lethal strains should promote the field release of transgenic strains having enhanced efficiency and safety.

Approach:
Transgenic tetracycline-suppressible female-specific and sperm-specific lethal systems for Anastrepha (A.) ludens and Drosophila (D.) suzukii will be created for development of male-only sexing strains that are sterile when reared on Tet-free diet. Transgenic tTA driver lines and lethal effector lines in A. ludens and D. suzukii will be created by piggyBac germ-line transformation and will be evaluated for female-specific and spermatocyte-specific lethality, and uni-sex lethality in D. suzukii, when reared on Tet-free diet. The frequency and genetic basis of lethality reversion resulting in survival of either sex under large-scale rearing will be determined for the D. suzukii Tet-off uni-sex embryonic lethality system. The efficacy of a secondary temperature-dependent conditional lethal system (DmDTS7), recombined into Tet-off driver and lethal effector vector cassettes, to suppress Tet-off revertant survival in D. suzukii will then be assessed.