Tachykinins (TKs), a conserved family of neuropeptides, play critical roles in regulating multiple physiological processes such as feeding and energy metabolism in insects. This study identified the TK gene (ApTK) from the Chinese oak silkworm, Antheraea pernyi, an economically important insect species. Bioinformatic analysis showed that ApTK possesses four FX1GX2R motifs (X1 and X2 represent variable amino acid residues), comprising FMGVR, FYGVR, FIGVR, and FFGMR, in the C-terminus and shares a close phylogenetic relationship with TKs from Bombyx mori and Manduca sexta. Tissue-specific expression profiling demonstrated that ApTK was mainly expressed in the brain and midgut. Starvation–refeeding experiments showed that the expression of ApTK was significantly upregulated during food deprivation and returned to baseline after refeeding, evincing its involvement in hunger signaling. RNA interference (RNAi)-mediated knockdown of ApTK led to a significant increase in larval body weight and increased levels of triglyceride, glycogen, and trehalose, indicating enhanced energy storage. Collectively, these results demonstrate that ApTK acts as a key regulator in restraining feeding and modulating energy homeostasis in A. pernyi. Our findings provide insights into the neuroendocrine mechanisms underlying feeding behavior and energy metabolism in A. pernyi.
Wang et al. (Sat,) studied this question.