UDP-N-acetylglucosamine pyrophosphorylase (UAP) is an essential enzyme in the insect chitin biosynthesis pathway; however, little is known regarding its molecular functions in Oedaleus asiaticus Bey-Bienko (Orthoptera: Acrididae). Here, two UAP genes, OaUAP1 and OaUAP2, were identified and characterized in O. asiaticus. The effects of exogenous treatments, including the molting hormone 20-hydroxyecdysone (20E) and the chitin biosynthesis inhibitor validamycin (VA), were assessed on chitin synthesis. Sequence analyses have shown that the cDNA and deduced amino acid sequences of O. asiaticus share over 90% identity with UAPs in Locusta migratoria. OaUAP1 and OaUAP2 are widely expressed in many tissues and developmental stages but exhibit different expression patterns: OaUAP1 shows higher expression in the epidermis and fifth-instar nymphs, while OaUAP2 is primarily expressed in the fat body and in the fifth-instar nymphs and adults. The functional analysis of two OaUAPs revealed that OaUAP2 was crucial in molting; moreover, its implication also exists in other biosynthetic processes since nymphs maintained normal growth and development. Both OaUAP expressions were upregulated by 20E and downregulated by VA in the chitin biosynthesis pathway. Our findings provide a vital molecular insight into the chitin biosynthesis pathway of O. asiaticus and lay a solid foundation for developing environmentally safe biological insecticides.
Gao et al. (2026) studied this question.