Synthesis Of Pheromone Research Articles

A Review of the Host Plant Location and Recognition Mechanisms of Asian Longhorn Beetle.

The Asian longhorn beetle (ALB), Anoplophora glabripennis Motschulsky, is a polyphagous xylophage with dozens of reported host tree species. However, the mechanisms by which individuals locate and recognize host plants are still unknown. We summarize the current knowledge of the host plant list, host kairomones, odorant-binding proteins (OBPs) and microbial symbionts of this beetle and their practical applications, and finally discuss the host localization and recognition mechanisms. A total of 209 species (or cultivars) were reported as ALB host plants, including 101 species of higher sensitivity; host kairomones were preferentially bound to ALB recombinant OBPs, including cis-3-hexen-1-ol, δ-3-carene, nonanal, linalool, and β-caryophyllene. In addition, microbial symbionts may help ALB degrade their host. Complementarity of tree species with different levels of resistance may reduce damage, but trapping effectiveness for adults was limited using a combination of host kairomones and sex pheromones in the field. Therefore, we discuss host location behavior from a new perspective and show that multiple cues are used by ALB to locate and recognize host plants. Further research into host resistance mechanisms and visual signal recognition, and the interaction of sex pheromone synthesis, symbiont microbiota, and host plants may help reveal the host recognition mechanisms of ALBs.

Overview of Kenji Mori's pheromone synthesis series.

It was the late Professor Kenji Mori, the giant of pheromone synthesis and pioneer of pheromone stereochemistry, who laid the foundation for the practical application of insect pheromones, which play an important role in Integrated Pest Management, one of the key concepts of agriculture in the 21st century. Therefore, it would be meaningful to retrace his achievements at this time, three and a half years after his death. In this review, we would like to introduce some of his notable synthetic studies from his Pheromone Synthesis Series and reconfirm his contributions to the development of pheromone chemistry and their impacts on natural science.

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry.

In the current ecological context, use of insect sex pheromones as an alternative to conventional pesticides is in constant growth. In this report, we discuss the recent contributions brought by our groups in the field of iron-catalyzed cross-couplings applied to the synthesis of insect pheromones. The pivotal question of the development of sustainable synthetic procedures involving cheap, non-toxic and efficient additives is also discussed, as well as the mechanistic features guiding the reactivity of such catalytic systems.

Asymmetric synthesis of sex pheromone of the western hemlock looper, Lambdina fiscellaria lugubrosa (Hulst)

The western hemlock looper is an economically important defoliator of coniferous trees. Its sex pheromone has been synthesized in 36–50% total yield using the enantiomers of 2-methyloxiraneoxide as chiral sources. The key steps of this strategy involved CuI catalyzed ring-opening of chiral 2-methyloxiraneoxide, stereospecific inversion of secondary tosylate and Wittig coupling of the aldehyde with chiral phosphonium salt. The synthetic pheromones would be used to monitor and control this pest.

Protein feeding mediates sex pheromone biosynthesis in an insect.

Protein feeding is critical for male reproductive success in many insect species. However, how protein affects the reproduction remains largely unknown. Using Bactrocera dorsalis as the study model, we investigated how protein feeding regulated sex pheromone synthesis. We show that protein ingestion is essential for sex pheromone synthesis in male. While protein feeding or deprivation did not affect Bacillus abundance, transcriptome analysis revealed that sarcosine dehydrogenase (Sardh) in protein-fed males regulates the biosynthesis of sex pheromones by increasing glycine and threonine (sex pheromone precursors) contents. RNAi-mediated loss-of-function of Sardh decreases glycine, threonine, and sex pheromone contents and results in decreased mating ability in males. The study links male feeding behavior with discrete patterns of gene expression that plays role in sex pheromone synthesis, which in turn translates to successful copulatory behavior of the males.

Recent advances in the synthesis of insect pheromones: an overview from 2013 to 2022.

Covering: 2013 to June 2022Pheromones are usually produced by insects in sub-microgram amounts, which prevents the elucidation of their structures by nuclear magnetic resonance (NMR). Instead, a synthetic reference material is needed to confirm the structure of the natural compounds. In addition, the provision of synthetic pheromones enables large-scale field trials for the development of environmentally friendly pest management tools. Because of these potential applications in pest control, insect pheromones are attractive targets for the development of synthetic procedures and the synthesis of these intraspecific chemical messengers has been at the core of numerous research efforts in the field of pheromone chemistry. The present review is a quick reference guide for the syntheses of insect pheromones published from 2013 to mid-2022, listing the synthesized compounds and highlighting current methodologies in organic synthesis, such as carbon-carbon coupling reactions, organo-transition metal chemistry including ring-closing olefin metathesis, asymmetric epoxidations and dihydroxylations, and enzymatic reactions.

Synthesis of the sex pheromone components of fall armyworm (Spodoptera frugiperda)

Main components of the sex pheromone of fall armyworm (Spodoptera frugiperda) contain (Z)-7-dodecen-1-yl acetate (Z7-12:OAc), (Z)-9-tetradecen-1-yl acetate (Z9-14:OAc), and (Z)-11-hexadecen-1-yl acetate (Z11-16:OAc) were succesfully synthesized with a total yield over 48% via 5 steps. The starting materials for the synthesis of pheromones were diols (1,6-hexandiol; 1,8-octandiol; 10-decandiol) and 1-alkyne (1-hexyne and 1-octyne). This purpose of the study was the extension of the carbon chain by alkylation of a terminal alkyne using the n-BuLi agent and the reduction of alkyne to (Z)-alkene using the Pd(dba)2/KOH/DMF catalyst without using the molecular hydrogen. In this case, KOH/DMF was the hydrogen source system to eliminate an alkyne to (Z)-alkene and give over 90% yield with the (Z)-configuration selectivity (> 99%). The extension reaction of the carbon chain was carried out at -78oC for 30 min. and then at room temperature for 2 h., the alkyne was reduced to (Z)-alkene at 145oC for 6 hours. After the deprotection of the alcohol group by ultrasound without further purification, the acetylation was performed with an efficiency over 84%. The (Z)-alkene configuration of the obtained compounds, examined by 1H NMR spectra, showed that the coupling constants were Jcis = 11,0 Hz and Jcis = 10,5 Hz for Z11-16:OAc, respectively; but Jcis = 11,0 Hz for the Z7-12:OAc and Z9-14:OAc. This preparation process of the (Z)-alkene pheromones opened an opportunity to control fall armyworms without polluting the environment in Vietnam.

Asymmetric synthesis of the sex pheromone of the apple leafminer, Lyonetia prunifoliella.

Lyonetia prunifoliella is a significant pest in orchards and damages apple. The sex pheromones of this pest were prepared via a new and concise method. The central to our method were Evans' chiral auxiliaries, the addition of chiral Grignard reagent to aldehyde and Wittig coupling.

Intertwining Olefin Thianthrenation with Kornblum/Ganem Oxidations: Ene‐type Oxidation to Furnish α,β‐Unsaturated Carbonyls

AbstractA widely applicable, practical, and scalable synthetic method for efficient ene‐type double oxidation of alkenes is reported via a two‐step alkenyl thianthrenium umpolung/Kornblum‐Ganem oxidation strategy. This chemo‐ and stereoselective procedure allows easy access to various α,β‐unsaturated carbonyls that may be otherwise difficult or cumbersome to synthesize by conventional methods. For α‐olefins, this metal‐free transformation can be tuned according to synthetic needs to produce either the elusive (Z)‐unsaturated aldehydes or their (E) counterparts. Moreover, this strategy has enabled streamlined synthesis of distinct butadienyl pheromones and kairomones.

Intertwining Olefin Thianthrenation with Kornblum/Ganem Oxidations: Ene-type Oxidation to Furnish α,β-Unsaturated Carbonyls.

A widely applicable, practical, and scalable synthetic method for efficient ene-type double oxidation of alkenes is reported via a two-step alkenyl thianthrenium umpolung/Kornblum-Ganem oxidation strategy. This chemo- and stereoselective procedure allows easy access to various α,β-unsaturated carbonyls that may be otherwise difficult or cumbersome to synthesize by conventional methods. For α-olefins, this metal-free transformation can be tuned according to synthetic needs to produce either the elusive (Z)-unsaturated aldehydes or their (E) counterparts. Moreover, this strategy has enabled streamlined synthesis of distinct butadienyl pheromones and kairomones.

Clock genes regulate mating activity rhythms in the vector mosquitoes, Aedes albopictus and Culex quinquefasciatus.

Endogenous circadian rhythms result from genetically-encoded molecular clocks, whose components and downstream output factors cooperate to generate cyclic changes in activity. Mating is an important activity of mosquitoes, however, the key aspects of mating rhythm patterns and their regulatory mechanisms in two vector mosquito species, Aedes albopictus and Culex quinquefasciatus, remain unclear. We determined and compared the diel mating activity rhythms of these two mosquito species and discovered that Ae. albopictus had mating peaks in the light/dark transition periods (ZT0-3 and ZT9-12), while Cx. quinquefasciatus only had a mating peak at ZT12-15. Knockouts of the clock (clk) orthologous genes (Aalclk and Cxqclk) resulted in phase delay or phase reversal of the mating peaks in Ae. albopictus and Cx. quinquefasciatus, respectively. In addition, the temporal expression pattern of the desaturase orthologous genes, desat1, in both mosquito species was also different in respective wild-type strains and showed phase changes similar to the mating rhythms in clk mutant strains. Inhibition of desat1 expression resulted in decreased mating activity in male mosquitoes of both species but not females. In addition, desat1 regulated cuticular hydrocarbons' synthesis in both species. Silencing desat1 in male Ae. albopictus resulted in decreases of nonadecane and tricosane, which promoted mating, with concomitant increases of heptacosane, which inhibited mating. Silencing desat1 in male Cx. quinquefasciatus also resulted in decreases of tricosane, which promoted mating. These results suggest that Aalclk and Cxqclk have significant roles in the mating activity rhythms in both Ae. albopictus and Cx. quinquefasciatus by regulating the temporal expression of the desat1 gene under LD cycles, which affects sex pheromone synthesis and mating. This work provides insights into the molecular regulatory mechanism of distinct mating rhythm of Ae. albopictus and Cx. quinquefasciatus and may provide a basis for the control of these two important vector mosquitoes.

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.

Asymmetric Synthesis of Contact Sex Pheromone of Tetropium fuscum and Its Enantiomer

Tetropium fuscum is a harmful forest pest and attacks spruces. The contact sex pheromone of this pest, (S)-11-methyl-heptacosane, and its enantiomer were synthesized via Evans’ chiral auxiliaries. The key steps of this approach included acylation of carboxylic acid, diastereoselective methylation of oxazolidinone amide, and Wittig coupling of the aldehyde with chiral phosphonium salt. The synthetic pheromones would have potential utility in the control of this pest.

Modular synthesis of the pheromone (2S,7S)-2,7-nonanediyl dibutyrate and its racemate and their field efficacy to control orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae).

Sudden outbreaks of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) cause huge wheat yield losses. Use of sex pheromones is more efficient than laborious egg counting to monitor these hidden-concealed insects. Quick synthesis of the sex pheromones is therefore required to meet the sudden outbreak needs. A synthetic approach of stereospecific and racemic S. mosellana pheromones was presented. This method afforded the stereospecific and racemic S. mosellana pheromones in three steps and high enantioselectivity (> 98% ee for (2S,7S)-2,7-nonanediyl dibutyrate) in less than 1 day with 74% and 73% overall yields, respectively, whereas most conventional methods require longer synthesis time with less than 40% yield. The synthesis routes could quickly and economically afford the pheromones, starting from synthon (S)-but-3-yn-2-ol (1a) or but-3-yn-2-ol (1b), through the same three-step processes of coupling, reduction, and esterification. The Y-tube olfactometer results showed significant attractiveness of the synthetic stereospecific and racemic sex pheromones to S. mosellana males relative to the blank control (P < 0.001). Field trials also demonstrated significant attractiveness of the synthetic stereospecific and racemic sex pheromones relative to the blank control (P < 0.001). This modular approach is conducive to the deployment of field traps and timely responses to S. mosellana outbreaks and can be a time-saving and cost-effective tool to manage S. mosellana. © 2022 Society of Chemical Industry.

Complex and Beautiful: Unraveling the Intricate Communication Systems Among Plants and Insects.

My research focuses on elucidating the chemical communication systems linking plants, herbivores, and natural enemies. My interests in integrating chemistry and agriculture led to my graduate studies in the emerging field of chemical ecology. My thesis research resulted in the identification, synthesis, and application of boll weevil sex pheromones. My research group subsequently developed chemical lures for more than 20 species of pest insects. I then shifted my focus to some of the first studies of the chemical signals produced by plants being attacked by herbivores. When insects feed, elicitors in the insects' oral secretions, such as volicitin, a fatty acid-amino acid conjugate elicitor, stimulate plants to release volatile organic compounds. Parasitoid wasps learn to associate these species-specific volatiles with their herbivore hosts. These volatiles also prime nearby plants to activate a faster and higher defense response upon attack. Throughout my career, I have collaborated with scientists from diverse disciplines to tackle fundamental questions in chemical ecology and create innovative solutions for insect management. Our collaborative research has fundamentally changed and improved our understanding of the ongoing coevolution of plants, their herbivores, and the natural enemies that attack those herbivores.

Surviving in the Brine: A Multi-Omics Approach for Understanding the Physiology of the Halophile Fungus Aspergillus sydowii at Saturated NaCl Concentration.

Although various studies have investigated osmoadaptations of halophilic fungi to saline conditions, only few analyzed the fungal mechanisms occurring at saturated NaCl concentrations. Halophilic Aspergillus sydowii is a model organism for the study of molecular adaptations of filamentous fungi to hyperosmolarity. For the first time a multi-omics approach (i.e., transcriptomics and metabolomics) was used to compare A. sydowii at saturated concentration (5.13 M NaCl) to optimal salinity (1 M NaCl). Analysis revealed 1,842 genes differentially expressed of which 704 were overexpressed. Most differentially expressed genes were involved in metabolism and signal transduction. A gene ontology multi-scale network showed that ATP binding constituted the main network node with direct interactions to phosphorelay signal transduction, polysaccharide metabolism, and transferase activity. Free amino acids significantly decreased and amino acid metabolism was reprogrammed at 5.13 M NaCl. mRNA transcriptional analysis revealed upregulation of genes involved in methionine and cysteine biosynthesis at extreme water deprivation by NaCl. No modifications of membrane fatty acid composition occurred. Upregulated genes were involved in high-osmolarity glycerol signal transduction pathways, biosynthesis of β-1,3-glucans, and cross-membrane ion transporters. Downregulated genes were related to the synthesis of chitin, mannose, cell wall proteins, starvation, pheromone synthesis, and cell cycle. Non-coding RNAs represented the 20% of the total transcripts with 7% classified as long non-coding RNAs (lncRNAs). The 42% and 69% of the total lncRNAs and RNAs encoding transcription factors, respectively, were differentially expressed. A network analysis showed that differentially expressed lncRNAs and RNAs coding transcriptional factors were mainly related to the regulation of metabolic processes, protein phosphorylation, protein kinase activity, and plasma membrane composition. Metabolomic analyses revealed more complex and unknown metabolites at saturated NaCl concentration than at optimal salinity. This study is the first attempt to unravel the molecular ecology of an ascomycetous fungus at extreme water deprivation by NaCl (5.13 M). This work also represents a pioneer study to investigate the importance of lncRNAs and transcriptional factors in the transcriptomic response to high NaCl stress in halophilic fungi.

Sex Pheromones of the Potato Tuber Moth (Phthorimaea operculella).

The potato tuber moth (Phthorimaea operculella) is a major potato pest. Its sex pheromones contain two chemical structures: 4E,7Z-tridecadiene-1-ol acetate (PTM1) and 4E,7Z,10Z-tridecatriene-1-ol acetate (PTM2). Increasing global consciousness of environmental protection is driving widespread attention to the possible use of these pheromones for sustainable pest management. This review summarizes research on the structure confirmation, field application, and chemical synthesis of the sex pheromones of the potato tuber moth. An efficient synthesis strategy of the two sex pheromones is proposed.

Enantioselective Bioreduction of 5-Hexen-2-one in Directional Synthesis of Insect Pheromones

Enantioselective Bioreduction of 5-Hexen-2-one in Directional Synthesis of Insect Pheromones

Transcriptome analysis and identification of sex pheromone biosynthesis and transport related genes in Atrijuglans hetaohei (Lepidoptera: Gelechioidea).

Atrijuglans hetaohei Yang (Lepidoptera: Gelechioidea) is one of the major pests that can seriously damage the walnut tree, leading to harvest loss. Sex pheromones regulate mating communication and reproduction in insects and provide targets for developing a novel pest control strategy. In this study, by transcriptomic sequencing and analysis of the female pheromone gland (PG) and male genitalia of A. hetaohei, we identified 92 putative genes, of which 7 desaturases (Dess), 8 fatty acyl reductases (FARs), 4 fatty acid synthetases (FASs), 2 aldehyde oxidases (AOXs), 4 acetyltransferases (ACTs), 1 chemosensory protein (CSP), and 2 odorant-binding proteins (OBPs) were predominantly expressed in the female PG, while 5 Dess, 11 FARs, 7 FASs, 6 AOXs, 1 ACT, and 1 CSP showed more robust expression in the male genitalia. Moreover, phylogenetic analysis revealed that 7 Dess and 1 FAR were grouped with genes involved in pheromone synthesis in other Lepidoptera species. Thus, we proposed that these candidate genes are possibly involved in the sex pheromone biosynthetic pathway in A. hetaohei. Our findings will provide a solid genetic basis for further exploring the function of the tissue-biased genes and may be useful to screen potential targets for interfering chemical communication in A. hetaohei.

Reinvestigation of sex pheromone biosynthesis in the moth Trichoplusiani reveals novel quantitative control mechanisms

Many species of moths have a common control mechanism for synthesizing sex pheromone: the circadian release of pheromone biosynthesis-activation neuropeptide (PBAN) that switches pheromone synthesis on/off during the day. One apparent exception to this is the noctuid moth Trichoplusia ni (Hübner), in which pheromone synthesis appears continuous through the photoperiod, with circadian release of PBAN controlling emission rate of pheromone during calling. Sex pheromone biosynthesis was reinvestigated in T. ni using stable isotope tracer-tracee and gland sampling techniques to ascertain how pheromone quantities in gland cells and on the gland cuticular surface varied and were controlled. It was found that (i) carbohydrate from adult female feeding is used to synthesize sex pheromone, (ii) most of the stored acetate ester pheromone component(s) is contained in gland cells, (iii) a large pool of pheromone is synthesized and stored through the photoperiod with a slow turnover rate, (iv) although pheromone is synthesized throughout the photoperiod, its rate can vary, influenced by release of PBAN and possibly by an unidentified head factor, with both affecting carbohydrate uptake into the acetyl CoA pheromone precursor pool, and (v) as suggested previously, PBAN also influences translocation of pheromone out of the cell to the cuticular surface, possibly by causing breakdown of intracellular lipid droplets storing pheromone molecules. This work suggests that the quantitative synthesis and emission of pheromone in T. ni, and possibly other moths, is regulated by multiple complementary biochemical mechanisms.