Exploration of Candidate Genes Involved in the Biosynthesis, Regulation and Recognition of the Male-Produced Aggregation Pheromone of Halyomorpha halys

SIMPLE SUMMARY: The brown marmorated stink bug, Halyomorpha halys, is an invasive insect pest native to Asia that was accidently introduced into North America and Europe. The male-produced aggregation pheromone of H. halys has great application potential in population monitoring and control of this pest. In this study, we carried out a comprehensive bioinformatics analysis to identify the candidate genes involved in the biosynthesis of the male-specific sesquiterpene aggregation pheromone of H. halys. We identified a novel gene, designated as HhTPS1, which is related to the synthesis of the precursor molecule of the aggregation pheromone. Moreover, potential P450 reductase and transcription factors related to the aggregation pheromone biosynthesis pathway were detected. In addition, two olfactory-related genes, chemosensory protein 5 (HhCSP5) and olfactory receptor 85b (HhOr85b), were also identified, which are assumed to be involved in the olfactory recognition of this pheromone. Our results lay a solid foundation for further elucidating the biosynthesis of this aggregation pheromone and its behavioral regulation of H. halys. ABSTRACT: The aggregation pheromone of the brown marmorated stink bug, Halyomorpha halys (Stål), is produced by adult males, and plays an important role in the behavioral regulation of H. halys. However, information on the molecular mechanisms underlying this pheromone’s biosynthesis is limited. In this study, HhTPS1, a key candidate synthase gene in the aggregation pheromone biosynthesis pathway of H. halys, was identified. Then, through weighted gene co-expression network analysis, the candidate P450 enzyme genes in the biosynthetic downstream of this pheromone and the related candidate transcription factor in this pathway were also identified. In addition, two olfactory-related genes, HhCSP5 and HhOr85b, involved in the recognition of the aggregation pheromone of H. halys, were detected. We further identified the key amino acid sites of HhTPS1 and HhCSP5 that interact with substrates by using molecular docking analysis. This study provides basic information for further investigations into the biosynthesis pathways and recognition mechanisms of aggregation pheromones in H. halys. It also provides key candidate genes for bioengineering bioactive aggregation pheromones necessary for the development of technologies for the monitoring and control of H. halys.