The stink bugs, (Pentatomidae) harlequin bug (Murgantia histrionica), brown marmorated stink bug (Halyomorpha halys), and southern green stink bug (Nezara viridula) are significant agricultural pests both in the United States and globally. The aggregation or sex pheromones produced by these insects are known to be bisabolene-type sesquiterpenoids; however, the biosynthetic pathways in the formation of these pheromones are unknown. Here we provide evidence that Pentatomidae produce sesquiterpene aggregation pheromones de novo and discuss the evolution of terpene biosynthesis in stink bugs. According to transcriptome analyses, the investigated stink bug species express at least two isoprenyl diphosphate synthases (IDSs), one of which makes (E,E)-farnesyl diphosphate (FPP) as the general precursor in sesquiterpene synthesis, whereas other IDS-type proteins function as terpene synthases (TPSs) generating intermediates in sesquiterpene pheromone formation. The TPS genes are expressed in a sex- and tissue-specific manner. Based on phylogenetic analysis, these IDS-type TPSs arose from trans-IDS progenitors in divergence from bona fide IDS proteins. Compared to microbes and plants, the evolution of TPS function from IDS progenitors in insects appears to have occurred more recently. The discovery of TPS genes in stink bugs provides valuable insight into pentatomid and insect terpene biosynthesis. Moreover, the identified genes may be used in developing alternative management strategies for stink bug pests. / PHD / The stink bugs harlequin bug, brown marmorated stink bug, and southern green stink bug are significant agricultural pests both in the United States and globally. These stink bugs, as many others, release terpene type pheromones for aggregation and mating. In contrast to the general notion that insects depend on their host plants or microbes as sources of terpene pheromones, we provide evidence that stink bugs produce these pheromones de novo. We found that stink bug pheromone formation depends on proteins with terpene synthase activity, which are derived from enzymes producing linear intermediates in the core terpene metabolic pathway (isoprenyl diphosphate synthases). Expression of the terpene synthase genes is confined to specific tissues of males according to the male-specific release of the pheromones. Compared to microbes and plants, the evolution of terpene synthase function from isoprenyl diphosphate synthase progenitors in insects appears to have occurred more recently. The discovery of terpene synthase genes in stink bugs provides valuable insight into pentatomid and insect terpene biosynthesis. Moreover, the identified genes may be used in developing alternative management strategies for stink bug pests.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/96290 |
| Date | 12 July 2018 |
| Creators | Lancaster, Jason |
| Contributors | Biological Sciences, Tholl, Dorothea, Winkel, Brenda S. J., Westwood, James H., Tu, Zhijian Jake |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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