The role of 20E biosynthesis relative gene Shadow in the reproduction of the predatory mirid bug, Cyrtorhinus lividipennis (Hemiptera: Miridae)

Cytorhinus lividipennis is a natural enemy of rice planthoppers and leafhoppers. Improving the fecundity of C. lividipennis will be helpful to improve its control effect on pests. However, little is known about the hormonal regulatory mechanism of reproduction in C. lividipennis. In the current study, we examined the role of 20-hydroxyecdysone (20E) biosynthesis relative gene Shadow in the reproduction of C. lividipennis. The complementary DNA sequence of ClSad is 2018 -bp in length with an open reading frame of 1398-bp encoding 465 amino acid residues. ClSad was readily detected in nymphal and adult stages, and highly expressed in the adult stage. ClSad was highly expressed in the midgut and ovaries of adult females. Moreover, RNA interference-mediated knockdown of ClSad reduced the 20E titers and ClVg transcript level, resulting in fewer fully developed eggs and a decrease in the number of eggs laid by dsSad-injected adult females within 15 days. These results suggest that ClSad plays a critical role in the reproduction of C. lividipennis. The present study provides insights into the molecular mechanism of the ClSad gene for the reproduction of C. lividipennis.