Germ-line transformation of the Queensland fruit fly, Bactrocera tryoni, using a piggyBac vector in the presence of endogenous piggyBac elements.

We report the heritable germ-line transformation of the Queensland fruit fly, Bactrocera tryoni, using a piggyBac vector marked with either the fluorescent protein DsRed or EGFP. A transformation frequency of 5-10% was obtained. Inheritance of the transgenes has remained stable over more than 15 generations despite the presence of endogenous piggyBac sequences in the B. tryoni genome. The sequence of insertion sites shows the usual canonical pattern of piggyBac integraton into TTAA target sites. An investigation of endogenous piggyBac elements in the B. tryoni genome reveals the presence of sequences almost identical to those reported recently for the B. dorsalis complex of fruit flies and two noctuid moths, suggesting a common origin of piggyBac sequences in these species. The availability of transformation protocols for B. tryoni has the potential to deliver improvements in the performance of the Sterile Insect Technique for this pest species.