Gene cloning and expression analysis of trehalose-6-phosphate synthase, glycogen synthase and glycogen phosphorylase reveal the glycometabolism in the diapause process of Aphidius gifuensis

Abstract Aphidius gifuensis is an important biological control agent of aphid. It stores sugar as energy reserves before the onset of diapause, a form of dormancy that occurs when environmental conditions become unfavorable for development. In this study, cDNA of three relevant enzymes, trehalose-6-phosphate synthase (TPS), glycogen synthase (GYS) and glycogen phosphorylase (GP) were cloned, and their expression profiles in the preparation and maintenance of diapause, and post-diapause development were analyzed. The results showed that AgTPS, AgGYS and AgGP encoded proteins consisting of 807, 690 and 844 amino acids respectively. The expression profiles of three genes were significantly affected by diapause-inducing condition. The increase of transcription of AgGYS and AgGP were followed by the up-regulate of AgTPS expression in the preparation of diapause, expression of all three genes were inhibited while diapause is maintained, and expression of AgGYS was up-regulated when diapause was terminated. These results suggested that trehalose is accumulated before initiation of diapause and glycogen may play an important role in post-diapause development.