Identification and Expression Analysis of the FAD Gene Family in Anoplophora glabripennis (Coleoptera: Cerambycidae) Based on Genome-Wide Data

Pheromones play an important role in mate choice in insects, and pheromone synthesis pathways are potential targets for the control of harmful insects, among which desaturation is of great significance in pheromone structural diversity. However, little is known about the desaturase genes regulating pheromone synthesis in Coleoptera. In this study, taking the internationally significant pest Anoplophora glabripennis as a research object, we identified 6 AglaFAD genes, all of which were mapped to the endoplasmic reticulum and shared a highly similar distribution of conserved domains. A phylogenetic analysis showed that AglaFAD1–2 and AglaFAD3–6 exerted desaturation at different positions of the acyl chain, respectively. In regard to the expression levels of these six AglaFADs in both sexes, six tissues and three developmental stages were analyzed by qPCR. Combined with the chemical composition of the female pheromones that have been identified, two candidate genes, AglaFAD2 and AglaFAD5, which are specifically expressed in females, were screened, showing higher expression levels before mating and significantly decreasing after mating. It is speculated that they may be involved in the biosynthesis of contact pheromones in females. These results provide a basis for detailed functional studies of candidate genes in insect pheromone synthesis.