Genome-Wide Identification and Expression Profiling of Candidate Sex Pheromone Biosynthesis Genes in the Fall Armyworm ( Spodoptera frugiperda ).

Spodoptera frugiperda is an agricultural pest causing substantial damage and losses to commercial crops. Sex pheromones are critical for successful mating in Lepidoptera and have been used for monitoring and control of many pest species. The sex pheromone of S. frugiperda is known, but the genes involved in its biosynthesis have not been identified. We systematically studied 99 candidate sex pheromone genes in the genome of S. frugiperda including 1 acetyl-CoA carboxylase (ACC), 11 fatty acid synthases (FASs), 17 desaturases (DESs), 4 fatty acid transport proteins (FATPs), 29 fatty acyl-CoA reductases (FARs), 17 acetyl-CoA acetyltransferases (ACTs), 5 acyl-CoA dehydrogenase (ACDs), 3 enoyl-CoA hydratases (ECHs), 3 hydroxyacyl-CoA dehydrogenases (HCDs), 6 ethyl-CoA thiolases (KCTs), and 3 acyl-CoA-binding proteins (ACBPs). Based on the comparative transcriptome results, we found 22 candidate sex pheromone biosynthesis genes predominately expressed in pheromone glands (PGs) than abdomens without PGs including SfruFAS4 , SfruFATP3 , SfruACD5 , SfruKCT3 , SfruDES2 , SfruDES5 , SfruDES11 , SfruDES13 , SfruFAR1 , SfruFAR2 , SfruFAR3 , SfruFAR6 , SfruFAR7 , SfruFAR8 , SfruFAR9 , SfruFAR10 , SfruFAR11 , SfruFAR14 , SfruFAR16 , SfruFAR29 , SfruACT6 , and SfruACT10 . A combination of phylogenetic and tissue-specific transcriptomic analyses indicated that SfruDES5 , SfruDES11 , SfruFAR2 , SfruFAR3 , and SfruFAR9 may be key genes involved in the sex pheromone synthesis of S. frugiperda . Our results could provide a theoretical basis for understanding the molecular mechanisms of sex pheromone biosynthesis in S. frugiperda , and also provide new targets for developing novel pest control methods based on disrupting sexual communication.