Germline transformation of the spotted wing drosophilid, Drosophila suzukii, with a piggyBac transposon vector.

Drosophila suzukii is a pest of small fruits in many parts of the world, whose management is limited to cultural practices and the use of insecticides. Here we describe a method to genetically manipulate this species in the first step to create female lethality strains useful for the sterile insect technique method of population suppression. This was achieved by the germ-line transformation of D. suzukii with a piggyBac transposon vector having a female-specific lethality effector construct. This can be used in a tetracycline-suppressible conditional gene expression system, when crossed to a suitable tet-transactivator strain. Transformation occurred efficiently, at a frequency of 16 % per fertile G0 embryo injected with vector and helper transposase plasmids. The vector was marked for transformant selection with the polyubiquitin-regulated EGFP fluorescent protein, and contains the attP landing site and heterospecific lox recombination sites for post-integration modification of the transgene vector. The 3xP3-AmCyan fluorescent protein marker was inserted within the lox sites to follow a possible recombinase-mediated cassette exchange, that would allow subsequent improvement of the transgenic strain by immobilization of the vector and introduction of new marker cassettes.