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Team:Valencia UPV/Project/modules/release
From 2014.igem.org
Project > Modules > Pheromone Release
We use sex pheromones to avoid sexual encounter in a strategy called mating disruption. However, producing the pheromone is not enough for this strategy to be effective, the pheromone must be released into the air. Sex pheromones concentration in the air has to reach high enough levels to cause mating disruption.
Even though pheromones are volatile compound, they still need to find a way out of the plant. For that reason, we decided to produce pheromones in epidermal organs called glandular trichomes to release volatile compounds into the air [1]. These organs are located in the surface of aerial parts of many higher plant species and contain higher concentration of secondary metabolites than an average cell in the plant (up to 15% of dry weight) [2] (Structure in figure 1). This characteristics make glandular trichomes great organs to release volatile compounds.
Figure 1. Structure of a glandular trichome. Glandular trichomes (right) are formed of a support structure holding one or several glandular cells. A glandular trichome from Digitalis purpurea, which contains only one glandular cell at the tip of the organ, is shown in the picture next to a non-glandular trichome (left).
Specific expression of sex pheromone biosynthetic pathways in glandular trichomes also decreased the disturbance in the plant’s metabolism. We accomplished specific expression in glandular trichomes under the regulation of the promoter PCPS2, from Nicotiana tabacum. PCPS2 naturally regulates transcription of a terpene synthase in glandular trichome cells with great specificity [3]. Expression in glandular trichomes is an elegant strategy to release pheromones into the air causing the minimum metabolic impact in the plant.
References
- Wagner GJ (1991) Secreting glandular trichomes: more than just hairs. Plant Physiol 96: 675-679.
- CEnnajdaoui H, Vachon G, Giacalone C, Besse I, Sallaud C, et al. (2010) Trichome specific expression of the tobacco (Nicotiana sylvestris) cembratrien-ol synthase genes is controlled by both activating and repressing cis-regions. Plant Mol Biol 73: 673-685.
- 3. Sallaud C, Giacalone C, Topfer R, Goepfert S, Bakaher N, et al. (2012) Characterization of two genes for the biosynthesis of the labdane diterpene Z-abienol in tobacco (Nicotiana tabacum) glandular trichomes. Plant J 72: 1-17.
