| Chitin is widely found in fungi, insects and crustaceans, but not in plants and vertebrates. It is an important component of insect exoskeleton, trachea and midgut peritrophic membrane. During the molting process of insects, chitin-rich structures need to be reconstructed to complete the expansion of the insect body, and the synthesis of chitin needs to be strictly controlled. Therefore, chitin biosynthesis has been an important target for pest control. With the rapid development of pesticide resistance in insect populations, pest prevention and control is facing new challenges, and it is necessary to constantly search for new pest control targets to develop new insecticides and achieve effective pest control. Chitin synthase (CHS) is a key enzyme in insect chitin synthesis pathway and plays an important role in chitin synthesis. There are two kinds of chitin synthases, CHS1 and CHS2. CHS1 is expressed in the exoskeleton and trachea of insects and catalyzes chitin synthesis, while CHS2 is mainly responsible for chitin synthesis in the midgut peritrophic membrane. Interference of CHS1 can lead to defects in insect epidermis and abnormal development of dorsal trunk of tracheae, while the inhibition of CHS2 often results in shorter midgut and weight loss. Down-regulation of both CHS genes in insects could cause a large number of deaths. Insects have complex transcriptional regulation mechanisms of CHS to ensure their normal growth and development, and respond to external stimuli. Based on domestic and foreign studies, we reviewed the research progress in transcriptional regulation of insect CHS, including the effects of insect hormones, transcription factors, epidermal injury and feeding stimulation, genes and substances related to chitin metabolism, microRNA, and inhibitors of chitin synthesis on CHS mRNA levels in insects, with an aim to provide a theoretical basis for the development and utilization of green pesticides targeting CHS for pest control in the future. |
