Location: Insect Behavior and Biocontrol Research
Project Number: 6036-22000-030-012-I
Project Type: Interagency Reimbursable Agreement
Start Date: Apr 1, 2016
End Date: Mar 31, 2022
The goal of this research is to improve and expand the development and ecological safety of transgenic insects created for improved biological control strategies. By seeking to manage the population size of highly significant invasive pest insects, this project aims to enhance the protection and safety of the Nation's agriculture and food supply. Genetically transformed insects provide significant opportunities to improve the sterile insect technique (SIT) using new strategies based on chemical and temperature-dependent conditional sexing and fertility. Tetracycline-dependent lethality systems will be used with female-specific and male-specific lethal genes to create transgenic strains in the Mexican fruit fly, Anastrepha ludens, and the spotted-winged drosophilid, Drosophila suzukii, to create strains in which females fail to survive embryogenesis and surviving males are sterilized due to spermatocyte lethality. Another approach using gene-editing of a sex-determination gene, will create temperature-dependent mutations resulting in chromosomal females developing as sterile males.
Transgenic strains for Anastrepha (A.) ludens and Drosophilia (D.) suzukii will be created using driver and lethal effector constructs for Tet-off female- and spermatocyte-specific lethality. Optimal strains will be mated to create hybrid driver/effector strains that will be tested for embryonic female-lethality with surviving males that are sterile on Tet-free diet. CRISPR/Cas9 gene-editing tools will be used to create lines for mutated transformer-2 cognates, in A. ludens and D. suzukii, whose function is temperature-dependent function. Two approaches include i) creating tra-2 gene cognate point mutations in conserved sites known to result in the Drosophila tra-2ts1 and tra-2ts2 mutations, and ii) knocking-out native tra-2 gene cognates with insertions of in vitro mutagenized tra-2ts alleles. XX; tra-2ts transformed lines will be evaluated for phenotypic sex-reversal to males at non-permissive temperature in terms of sex-specific gene expression, mating behavior and fertility.