Silencing the Triacylglycerol Lipase (TGL) Gene Decreases the Number of Apyrene Sperm and Inhibits Oviposition in Sitotroga Cerealella

Abstract

Triacylglycerol lipase (TGL) is an essential lipid metabolism enzyme that also plays a critical role in energy metabolism; however, how it regulates other life processes is unknown. To investigate the functional role of TGL in moth reproduction, males Sitotroga cerealella were used as a model. The TGL gene was cloned and analysed. The results showed that the open reading frame of TGL was 1968 bp long and contained three conserved regions. TGL gene expression was higher in the larval and early adult stages than in the pupal stage, with the highest levels observed in the fat body, testis and accessory glands during the early adult stage. Moreover, after TGL in male adults was silenced through RNAi, the protein content in male accessory glands remained unchanged, and the spermatophore transferred into females mated with TGL -silenced males became small and empty; meanwhile, the number of apyrene sperm in the spermatophore was significantly reduced due to the reduction of apyrene sperm in males, which eventually led to the significant reduction of egg laying amount. All of the findings suggest that TGL regulates the amount of sperm in male moths as well as the morphology and quality of spermatophores transferred to females after mating with treated males, implying that TGL is critical for Sitotroga cerealella’s reproductive process.