A functional study of the trehalase genes in Tribolium castaneum and their application in the construction of RNAi engineering bacteria

Tribolium castaneum, belonging to the order Coleoptera, family Tenebrionidae, is a global grain storage pest. The enzyme trehalase can catalyze trehalose decomposition and participate in chitin synthesis, which is of great significance in insect physiology and may be a key target for T. castaneum pest prevention and control. This study focused on T. castaneum and explored the function of its trehalase (TcTre) in test insects' growth and development process. We analyzed the roles of TcTre in different growth stages and tissues of T. castaneum by measuring its spatio and temporal expression patterns. The silencing of TcTre by RNAi technology reduced the transcription level of the target gene, affected the enzyme activity of trehalase, disturbed the sugar balance, blocked the pathway of chitin synthesis, and caused abnormal molting and wing development of the tested insects. Key genes about pest control such as TcTre1–1, TcTre1–3, and TcTre2 were screened, which caused the accumulated mortality of 53.33 %, 56.67 %, and 50.00 % respectively. Subsequently, an engineered bacterium, Tre-L4440-HT115 (DE3), was developed to efficiently express dsRNA and mediate insecticidal activity. The dsRNA produced by the bacterial solution, targeting TcTre1–1, TcTre1–3, and TcTre2 fragments for silencing, could cause the death of 44.44 %, 48.89 %, and 46.67 % of the test insects cumulatively. This advancement was aimed at reducing the production costs of dsRNA and laying a scientific foundation for the industrial development of nucleic acid pesticides for T. castaneum.