LAUSR

Two physiological changes of Spodoptera litura parasitized by Microplitis bicoloratus are hemocyte-apoptosis and retarded immature development. β-Chain of Fo F1 -ATPase was found from a S. litura transcriptome. It belongs to a conserved P-loop NTPase superfamily, descending from a common ancestor of Lepidopteran clade. However, the characterization of β-chain of ATPase in apoptotic cells and its involvement in development remain unknown. Here, the ectopic expression and endogenous Fo F1 -ATPase β-chain occurred on S. litura cell membrane: in vivo, at the late stage of apoptotic hemocyte, endogenous Fo F1 -ATPase β-chain was stably expressed during M. bicoloratus larva development from 4 to 7 days post-parasitization; in vitro, at an early stage of pre-apoptotic Spli221 cells by infecting with M. bicoloratus bracovirus particles, the proteins were speedily recover expression. Furthermore, endogenous Fo F1 -ATPase β-chain was localized on the apoptotic cell membrane. RNA interference (RNAi) of Fo F1 -ATPase β-chain led to significantly decreased head capsule width. This suggested that Fo F1 -ATPase β-chain positively regulated the development of S. litura. The RNAi effect on the head capsule width was enhanced with parasitism. Our research found that Fo F1 -ATPase β-chain was expressed and localized on the cell membrane in the apoptotic cells, and involved in the development of S. litura.