Identification and Characterization of Troponin T Associated with Development, Metabolism and Reproduction in Tribolium castaneum

As a tropomyosin-binding component, troponin T (TnT) is essential for the Ca²⁺ regulation of striated muscles' contraction and locomotion activity, but its impacts on the growth and development of insects have rarely been reported. In this study, <i>TnT</i> was identified and functionally characterized in <i>Tribolium castaneum</i> by RNA interference (RNAi) and transcriptome analysis. The <i>TnT</i> of <i>T. castaneum</i> contained a 1152 bp open reading frame encoding 383 amino acids. It displayed the highest expression in late pupae and was highly expressed in the integument and CNS. Both the larval and early pupal injection of ds<i>TnT</i> led to 100% cumulative mortality before the pupal-adult transition. Late pupal RNAi caused 26.01 ± 4.29% pupal mortality; the survivors successfully became adults, but 49.71 ± 6.51% died in 10 days with a dried and shriveled abdomen, poorly developed reproductive system and no offspring. Additionally, RNA sequencing results indicated that key ecdysteroid and juvenile hormone biosynthesis genes (<i>CYP314A1</i>, <i>aldehyde dehydrogenase family 3 member B1</i> and <i>farnesol dehydrogenase</i>) were affected, as well as several cuticle protein, nutrition metabolism and immune-related genes, suggesting that <i>TnT</i> may play prominent roles in development, metabolism and reproduction by affecting these pathways. This study could provide a brand-new target gene in the RNAi strategy for pest control.