TheBactrocera dorsaliscaspase-1gene is expressed throughout development and required for female fertility

Abstract

BACKGROUND The oriental fruit flyBactrocera dorsalisis one of the most destructive pests of fruits and vegetables. The sterile insect technique (SIT) is an effective and environmentally friendly approach to the control of tephritid fruit flies. The pro-apoptotic genehead involution defective(hid) has been used as an effective lethal effector in SIT. It initiates an interaction cascade including activation of caspase-like proteases. However, the biological role of caspase activity in tephritid fruit flies has yet to be explored. RESULTS In this study, theB. dorsalis caspase-1gene (Bdcp-1) was cloned and characterized. Sequence comparison showed that Bdcp-1 protein shared highly homology withDrosophilaeffector caspases Drice and Dcp-1. It is predicted to contain a short pro-domain because two proteolytic cleavage sites (Asp(16)and Asp(223)) are present. Expression patterns indicated thatBdcp-1is highly transcribed in embryos and expression was upregulated during metamorphosis and upon ultraviolet irradiation. RNA interference showed thatBdcp-1is essential for ovarian development and female fertility. For example, knockdown ofBdcp-1caused transcriptional downregulation of expression of theyolk protein-1gene (Bdyp-1) and delayed ovarian development. The percentage of spawning females and female fecundity were significantly reduced. CONCLUSION This study illustrates the function of theBdcp-1gene and provides an attractive method to develop a biological way to control the oriental fruit fly through the control of caspases.