The serine/threonine kinase CcAkt regulates the fertility ofCoridius chinensis

Abstract

Akt (also known as protein kinase B) belongs to the multifunctional serine/threonine kinase family and is an important component of the insulin signaling pathway that plays a key role in many biological processes such as cell growth, proliferation, and survival. However, few studies have reported the effect of Akt on reproduction in Hemiptera. In this study, we cloned and characterized theAktgene fromCoridius chinensis(CcAkt). The open reading frame ofCcAkthas a length of 1,563 bp and encodes 520 amino acids. It has a conserved pleckstrin homology domain, a serine/threonine protein kinase catalytic domain, and a serine/threonine protein kinase domain. Phylogenetic analysis showed thatCcAktandHhAktofHalyomorpha halyshad the highest similarity. Analysis of temporal and spatial expression patterns revealed thatCcAktis expressed throughout development and in various tissues ofC. chinensisadults.CcAktexpression was high in female adult and the fourth instar nymph stage ofC. chinensis. InC. chinensisadult,CcAktexpression was highest in the testis and ovary. Injection of bovine insulin inducedCcAktexpression, whereas that of 20-hydroxyecdysone significantly reducedCcAktexpression. Both hormones, however, induced the expression ofvitellogenin(Vg) andvitellogenin receptor(VgR). In unmated females,CcAktknockout resulted in decreased expression ofCcVgandCcVgR, stunted the development of the ovarioles, decreased the number of eggs and hatching rate. These findings suggest that CcAkt may be involved in regulating the reproduction ofC. chinensis.