Assessment of Ubiquitous Promoters Driving Fluorescent Marker and Transposase Expression to Develop a High-Performance piggyBac Transgenic System in Bactrocera dorsalis

<i>Bactrocera dorsalis</i> (oriental fruit fly) is a destructive invasive pest threatening global agriculture. Although integrated pest management is applied, environmentally friendly genetic control methods are urgently needed. The development of such methods particularly relies on efficient genetic elements. In this study, we compared the transient expression of mScarlet-I driven by various <i>Actin</i> and <i>PUb</i> promoters in <i>B. dorsalis</i> embryos. The truncation of two strong promoters, <i>BdActA3a</i> and <i>BdPUb</i>, revealed that the 5.0-kb <i>BdActA3a</i> and 3.6-kb <i>BdPUb</i> promoters drove significantly higher expression than their truncated variants. Notably, the <i>BdPUb</i> promoter was highly effective in driving fluorescent protein expression in <i>B. dorsalis</i>. Using the 3.6-kb <i>BdPUb</i> promoter, we constructed a transposase plasmid <i>BdPUb</i>-3.6 kb><i>hyPBase</i>. By co-injecting the <i>BdPUb</i> 3.6kb><i>mScarlet-I</i> donor construct, we successfully generated a fluorescent transgenic strain with a transgenic efficiency of approximately 26%. The strain exhibited stage-specific fluorescence and maternal effect and the homozygotes showed fecundity comparable to wild-type controls. The high performance of the <i>piggyBac</i> transposase and the fluorescence screening system provides a substantial technical foundation for basic research and future development of genetically modified strains to control <i>B. dorsalis</i>.