Introduction of the RTA‐Bddsx gene induces female‐specific lethal effects in transformed Bactrocera dorsalis (Hendel)

BACKGROUND:The oriental fruit fly, Bactrocera dorsalis (Hendel), can reduce fruit production and quality and is considered to be a major insect pest in many Asian countries. A system combining the toxicity of ricin and the alternative RNA splicing properties of doublesex (RTA-Bddsx) has been proposed that results in differential sexual processing in vitro. A transgenic approach was used in this study to confirm the existence of female-specific lethal effects in vivo. RESULTS: The piggyBac-based vector PB-Acp-CF21-26, which carries the actin 5C promoter and RTA-Bddsx, was used to establish transgenic lines. Five surviving male flies (F1) demonstrated the presence of selection marker Ds-Red((+)) throughout their entire bodies following single-pair mating with wild-type females, indicating germline transmission. A high percentage of males (59.6-100%) were observed in transformed F3 offspring, and this skewed sex ratio indicated that the female-lethal effects of the RTA-Bddsx system were heritable and functioned well in B. dorsalis. Some transformed female flies were observed, and these unexpected results were attributed to the loss of the intact transgene after genomic PCR analyses. CONCLUSION: This transgenic study provides direct evidence for the female-specific lethal effects of RTA-Bddsx in B. dorsalis and offers a novel and promising approach for the control of B. dorsalis in the future. (C) 2015 Society of Chemical Industry