8,10-Dodecadien-1-ol: Green Production and Its Core Applications

8,10-Dodecadien-1-ol is an unsaturated fatty alcohol containing twelve carbon atoms, featuring two carbon-carbon double bonds. Widely used as an aroma precursor in the fragrance industry, it is also investigated for insect behavior regulation.

Green Chemistry Production of 8,10-Dodecadien-1-ol

Pheromones have been used in Integrated Pest Management (IPM) for several decades as environmentally friendly, species-specific, non-toxic, and with a low risk of pests evolving resistance. The global agricultural pheromones market size was valued at $ 1.9 billion in 2017 and is estimated to reach $ 6.2 billion by the end of 2025. Some of the C12 moth pheromones are biosynthesized in insects by introduction of double bonds in longer fatty acid homologues followed by subsequent chain shortening (Bjostad and Roelofs 1983) and modification of the functional group, whereas others are biosynthesized by direct desaturation of lauric acid (12:0) and conversion of the immediate fatty acyl precursor into the actual pheromone component(s). The latter alternative holds for 8,10-Dodecadien-1-ol, the major pheromone component of the codling moth, C. pomonella, identified as (E,E)-8,10-dodecadienol (E8,E10-12:OH) by Roelofs et al.. A ∆9 desaturase gene Cpo_CPRQ acting on 12:0 is pivotal in 8,10-Dodecadien-1-ol biosynthesis, accounting for both double bonds in even positions.  The first effective pheromone dispenser for mating disruption of codling moth was registered in the United States in 1991 and since then mating disruption with synthetic 8,10-Dodecadien-1-ol has become an integral part of codling moth management in apple and pear orchards in many regions. Reviewing the impact of sex pheromones in pest control, Witzgall et al. reported that 210,000 ha of orchards were treated worldwide with mating disruption against codling moth, an area second only to the areas treated against the gypsy moth Lymantria dispar.[1]

When compared to synthetic 8,10-Dodecadien-1-ol, the plant-derived codlemone performed well without purification, both in the flight tunnel assay and in the field experiments considering that the sample contained very large amounts of saturated alcohols of different chain-length as well as the oleyl, linolyl and linolenoyl alcohols, in addition to the E9-12:OH and the codlemone. The overall purity of codlemone (E8,E10-12:OH) in this unprocessed batch was only 2.5% and the isomeric purity (%EE isomer) was 81%. Still this bait trapped 30% as many males as the conventionally produced 8,10-Dodecadien-1-ol which had an overall chemical purity above 95% and isomeric purity of 98%. The EAD analysis did not reveal any EAD active impurities in addition to 12:OH and the presence of 12:OH may not even be a problem. Dodecanol is present also in pheromone gland extracts albeit in lower relative amounts, and addition of this compound actually increased the attractiveness of the 8,10-Dodecadien-1-ol. In conclusion, we demonstrated the feasibility of producing mono- and di-unsaturated C12 moth pheromone precursors in transgenic plants. Using Camelina as the production platform for E8,E10-12:acid, we obtained levels of ≥ 8.5% of total fatty acids in seeds of the T2 generation.

The screening for Grapholita molesta pheromone synergists

Pheromone-based management is a leading nonpesticidal strategy among integrated pest management options. Improving the potency of pheromone products by adding synergists would be a practical way to popularize pheromone-based management as well as to reduce pesticide use. Using reverse chemical ecology, synergists for Grapholita molesta sex pheromone were screened. Combined molecular docking and in vitro binding assay led to the determination of four potentially active odorants showing high affinity to G. molesta pheromone binding protein 2 (GmolPBP2). Thereafter, the high affinity between 8,10-Dodecadien-1-ol and GmolPBP2 was further verified by exploration of GmolPBP2-Codlemone interactions. As the only sex pheromone synergist validated by both laboratory behavioral tests and field trapping, 8,10-Dodecadien-1-ol was used to optimize commercial sex attractants currently used in G. molesta control.[2]

The recommended formulation [(Z)-8-dodecenyl acetate:(E)-8-dodecenyl acetate: 8,10-Dodecadien-1-ol = 95:4:10] was found to trap about five to six times more G. molesta adults than the commercial sex attractant [(Z)-8-dodecenyl acetate:(E)-8-dodecenyl acetate: (Z)-8-dodecenol = 95:4:1]. 8,10-Dodecadien-1-ol is an excellent pheromone synergist that can be potentially sensed by GmolPBP2, which can remarkably improve the potency of G. molesta sex attractants. It is believed that the introduction of reverse chemical ecology would increase the chance of discovering pheromone synergists, promoting the development of more efficacious pheromone products that can be used in controlling G. molesta and beyond. © 2021 Society of Chemical Industry.

References

[1]Xia YH, Wang HL, Ding BJ, Svensson GP, Jarl-Sunesson C, Cahoon EB, Hofvander P, Löfstedt C. Green Chemistry Production of Codlemone, the Sex Pheromone of the Codling Moth (Cydia pomonella), by Metabolic Engineering of the Oilseed Crop Camelina (Camelina sativa). J Chem Ecol. 2021 Dec;47(12):950-967. doi: 10.1007/s10886-021-01316-4. Epub 2021 Nov 11. PMID: 34762210; PMCID: PMC8642345.

[2]Liu J, Zhou T, Li C, Li R, Ye X, Tian Z. Reverse chemical ecology guides the screening for Grapholita molesta pheromone synergists. Pest Manag Sci. 2022 Feb;78(2):643-652. doi: 10.1002/ps.6674. Epub 2021 Oct 30. PMID: 34658157.

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