NONSTOP GLUMES1 Encodes a C2H2 Zinc Finger Protein That Regulates Spikelet Development in Rice.

The spikelet is an inflorescence structure unique to grasses. The molecular mechanisms underlying spikelet development and evolution are unclear. In this study, we characterized three allelic recessive mutants in rice (Oryza sativa): nonstop glumes 1-1 (nsg1-1), nsg1-2, and nsg1-3 In these mutants, organs such as the rudimentary glume, sterile lemma, palea, lodicule, and filament were elongated and/or widened, or transformed into lemma- and/or marginal region of the palea-like organs. NSG1 encoded a member of the C2H2 zinc finger protein family and was expressed mainly in the organ primordia of the spikelet. In the nsg1-1 mutant spikelet, LHS1 DL, and MFO1 were ectopically expressed in two or more organs, including the rudimentary glume, sterile lemma, palea, lodicule, and stamen, whereas G1 was downregulated in the rudimentary glume and sterile lemma. Furthermore, the NSG1 protein was able to bind to regulatory regions of LHS1 and then recruit the corepressor TOPLESS-RELATED PROTEIN to repress expression by downregulating histone acetylation levels of the chromatin. The results suggest that NSG1 plays a pivotal role in maintaining organ identities in the spikelet by repressing the expression of LHS1, DL, and MFO1.

Ionotropic receptors in the turnip moth Agrotis segetum respond to repellent medium-chain fatty acids.

BACKGROUND: In insects, airborne chemical signals are mainly detected by two receptor families, odorant receptors (ORs) and ionotropic receptors (IRs). Functions of ORs have been intensively investigated in Diptera and Lepidoptera, while the functions and evolution of the more ancient IR family remain largely unexplored beyond Diptera. RESULTS: Here, we identified a repertoire of 26 IRs from transcriptomes of female and male antennae, and ovipositors in the moth Agrotis segetum. We observed that a large clade formed by IR75p and IR75q expansions is closely related to the acid-sensing IRs identified in Diptera. We functionally assayed each of the five AsegIRs from this clade using Xenopus oocytes and found that two receptors responded to the tested ligands. AsegIR75p.1 responded to several compounds but hexanoic acid was revealed to be the primary ligand, and AsegIR75q.1 responded primarily to octanoic acid, and less so to nonanoic acid. It has been reported that the C6-C10 medium-chain fatty acids repel various insects including many drosophilids and mosquitos. We show that the C6-C10 medium-chain fatty acids elicited antennal responses of both sexes of A. segetum, while only octanoic acid had repellent effect to the moths in a behavioral assay. In addition, using fluorescence in situ hybridization, we demonstrated that the five IRs and their co-receptor AsegIR8a are not located in coeloconic sensilla as found in Drosophila, but in basiconic or trichoid sensilla. CONCLUSIONS: Our results significantly expand the current knowledge of the insect IR family. Based on the functional data in combination with phylogenetic analysis, we propose that subfunctionalization after gene duplication plays an important role in the evolution of ligand specificities of the acid-sensing IRs in Lepidoptera.

Release of moth pheromone compounds from Nicotiana benthamiana upon transient expression of heterologous biosynthetic genes.

BACKGROUND: Using genetically modified plants as natural dispensers of insect pheromones may eventually become part of a novel strategy for integrated pest management. RESULTS: In the present study, we first characterized essential functional genes for sex pheromone biosynthesis in the rice stem borer Chilo suppressalis (Walker) by heterologous expression in Saccharomyces cerevisiae and Nicotiana benthamiana, including two desaturase genes CsupYPAQ and CsupKPSE and a reductase gene CsupFAR2. Subsequently, we co-expressed CsupYPAQ and CsupFAR2 together with the previously characterized moth desaturase Atr∆11 in N. benthamiana. This resulted in the production of (Z)-11-hexadecenol together with (Z)-11-hexadecenal, the major pheromone component of C. suppressalis. Both compounds were collected from the transformed N. benthamiana headspace volatiles using solid-phase microextraction. We finally added the expression of a yeast acetyltransferase gene ATF1 and could then confirm also (Z)-11-hexadecenyl acetate release from the plant. CONCLUSIONS: Our results pave the way for stable transformation of plants to be used as biological pheromone sources in different pest control strategies.

Manufacturing specialized wax esters in plants.

Biologically produced wax esters can fulfil different industrial purposes. These functionalities almost drove the sperm whale to extinction from hunting. After the ban on hunting, there is a niche in the global market for biolubricants with properties similar to spermaceti. Wax esters can also serve as a mechanism for producing insect sex pheromone fatty alcohols. Pheromone-based mating disruption strategies are in high demand to replace the toxic pesticides in agriculture and manage insect plagues threatening our food and fiber reserves. In this study we set out to investigate the possibilities of in planta assembly of wax esters, for specific applications, through transient expression of various mix-and-match combinations of genes in Nicotiana benthamiana leaves. Our synthetic biology designs were outlined in order to pivot plant lipid metabolism into producing wax esters with targeted fatty acyl and fatty alcohols moieties. Through this approach we managed to obtain industrially important spermaceti-like wax esters enriched in medium-chain fatty acyl and/or fatty alcohol moieties of wax esters. Via employment of plant codon-optimized moth acyl-CoA desaturases we also managed to capture unusual, unsaturated fatty alcohol and fatty acyl moieties, structurally similar to moth pheromone compounds, in plant-accumulated wax esters. Comparison between outcomes of different experimental designs identified targets for stable transformation to accumulate specialized wax esters and helped us to recognize possible bottlenecks of such accumulation.

MULTI-FLORET SPIKELET 2, a MYB Transcription Factor, Determines Spikelet Meristem Fate and Floral Organ Identity in Rice.

An understanding of flower and panicle development is crucial for improving yield and quality in majority of grass crops. In this study, we used mapping-based cloning to identify MULTI-FLORET SPIKELET2 (MFS2), which encodes a MYB transcription factor and regulates flower and spikelet development in rice (Oryza sativa). In the mfs2 mutant, specification of palea identity was severely disturbed and showed degradation or transformation into a lemma-like organ, and the number of all floral organs was increased to varying degrees. Due to the increase in the number of floral organs and development of extra transformed palea/marginal region of the palea-like organs, some mfs2 spikelets had a tendency to produce two florets. These defects implied that the mfs2 mutation caused abnormal specification of palea identity and partial loss of spikelet determination. We confirm that MFS2 is a transcriptional repressor that shows strong repression activity by means of two typical ethylene-responsive element binding factor-associated amphiphilic motifs, one of which locates at the C terminus and is capable of interaction with three rice TOPLESS and TOPLESS-related proteins. The results indicate that MFS2 acts as a repressor that regulates floral organ identities and spikelet meristem determinacy in rice by forming a repression complex with rice TOPLESS and TOPLESS-related proteins.

Green Chemistry Production of Codlemone, the Sex Pheromone of the Codling Moth (Cydia pomonella), by Metabolic Engineering of the Oilseed Crop Camelina (Camelina sativa).

Synthetic pheromones have been used for pest control over several decades. The conventional synthesis of di-unsaturated pheromone compounds is usually complex and costly. Camelina (Camelina sativa) has emerged as an ideal, non-food biotech oilseed platform for production of oils with modified fatty acid compositions. We used Camelina as a plant factory to produce mono- and di-unsaturated C12 chain length moth sex pheromone precursors, (E)-9-dodecenoic acid and (E,E)-8,10-dodecadienoic acid, by introducing a fatty acyl-ACP thioesterase FatB gene UcTE from California bay laurel (Umbellularia californica) and a bifunctional ∆9 desaturase gene Cpo_CPRQ from the codling moth, Cydia pomonella. Different transgene combinations were investigated for increasing pheromone precursor yield. The most productive Camelina line was engineered with a vector that contained one copy of UcTE and the viral suppressor protein encoding P19 transgenes and three copies of Cpo_CPRQ transgene. The T2 generation of this line produced 9.4% of (E)-9-dodecenoic acid and 5.5% of (E,E)-8,10-dodecadienoic acid of the total fatty acids, and seeds were selected to advance top-performing lines to homozygosity. In the T4 generation, production levels of (E)-9-dodecenoic acid and (E,E)-8,10-dodecadienoic acid remained stable. The diene acid together with other seed fatty acids were converted into corresponding alcohols, and the bioactivity of the plant-derived codlemone was confirmed by GC-EAD and a flight tunnel assay. Trapping in orchards and home gardens confirmed significant and specific attraction of C. pomonella males to the plant-derived codlemone.

Biosynthesis of the Sex Pheromone Component (E,Z)-7,9-Dodecadienyl Acetate in the European Grapevine Moth, Lobesia botrana, Involving ∆11 Desaturation and an Elusive ∆7 Desaturase.

The European grapevine moth, Lobesia botrana, uses (E,Z)-7,9-dodecadienyl acetate as its major sex pheromone component. Through in vivo labeling experiments we demonstrated that the doubly unsaturated pheromone component is produced by ∆11 desaturation of tetradecanoic acid, followed by chain shortening of (Z)-11-tetradecenoic acid to (Z)-9-dodecenoic acid, and subsequently introduction of the second double bond by an unknown ∆7 desaturase, before final reduction and acetylation. By sequencing and analyzing the transcriptome of female pheromone glands of L. botrana, we obtained 41 candidate genes that may be involved in sex pheromone production, including the genes encoding 17 fatty acyl desaturases, 13 fatty acyl reductases, 1 fatty acid synthase, 3 acyl-CoA oxidases, 1 acetyl-CoA carboxylase, 4 fatty acid transport proteins and 2 acyl-CoA binding proteins. A functional assay of desaturase and acyl-CoA oxidase gene candidates in yeast and insect cell (Sf9) heterologous expression systems revealed that Lbo_PPTQ encodes a ∆11 desaturase producing (Z)-11-tetradecenoic acid from tetradecanoic acid. Further, Lbo_31670 and Lbo_49602 encode two acyl-CoA oxidases that may produce (Z)-9-dodecenoic acid by chain shortening (Z)-11-tetradecenoic acid. The gene encoding the enzyme introducing the E7 double bond into (Z)-9-dodecenoic acid remains elusive even though we assayed 17 candidate desaturases in the two heterologous systems.

Production of moth sex pheromones for pest control by yeast fermentation.

The use of insect sex pheromones is an alternative technology for pest control in agriculture and forestry, which, in contrast to insecticides, does not have adverse effects on human health or environment and is efficient also against insecticide-resistant insect populations. Due to the high cost of chemically synthesized pheromones, mating disruption applications are currently primarily targeting higher value crops, such as fruits. Here we demonstrate a biotechnological method for the production of (Z)-hexadec-11-en-1-ol and (Z)-tetradec-9-en-1-ol, using engineered yeast cell factories. These unsaturated fatty alcohols are pheromone components or the immediate precursors of pheromone components of several economically important moth pests. Biosynthetic pathways towards several pheromones or their precursors were reconstructed in the oleaginous yeast Yarrowia lipolytica, which was further metabolically engineered for improved pheromone biosynthesis by decreasing fatty alcohol degradation and downregulating storage lipid accumulation. The sex pheromone of the cotton bollworm Helicoverpa armigera was produced by oxidation of fermented fatty alcohols into corresponding aldehydes. The resulting yeast-derived pheromone was just as efficient and specific for trapping of H. armigera male moths in cotton fields in Greece as a conventionally produced synthetic pheromone mixture. We further demonstrated the production of (Z)-tetradec-9-en-1-yl acetate, the main pheromone component of the fall armyworm Spodoptera frugiperda. Taken together our work describes a biotech platform for the production of commercially relevant titres of moth pheromones for pest control via yeast fermentation.

Role of PGC-1α in Mitochondrial Quality Control in Neurodegenerative Diseases.

As one of the major cell organelles responsible for ATP production, it is important that neurons maintain mitochondria with structural and functional integrity; this is especially true for neurons with high metabolic requirements. When mitochondrial damage occurs, mitochondria are able to maintain a steady state of functioning through molecular and organellar quality control, thus ensuring neuronal function. And when mitochondrial quality control (MQC) fails, mitochondria mediate apoptosis. An apparently key molecule in MQC is the transcriptional coactivator peroxisome proliferator activated receptor γ coactivator-1α (PGC-1α). Recent findings have demonstrated that upregulation of PGC-1α expression in neurons can modulate MQC to prevent mitochondrial dysfunction in certain in vivo and in vitro aging or neurodegenerative encephalopathy models, such as Huntington's disease, Alzheimer's disease, and Parkinson's disease. Because mitochondrial function and quality control disorders are the basis of pathogenesis in almost all neurodegenerative diseases (NDDs), the role of PGC-1α may make it a viable entry point for the treatment of such diseases. This review focuses on multi-level MQC in neurons, as well as the regulation of MQC by PGC-1α in these major NDDs.

Multi-Functional Desaturases in Two Spodoptera Moths with ∆11 and ∆12 Desaturation Activities.

The beet armyworm, Spodoptera exigua, uses (Z,E)-9,12-tetradecadienyl acetate as the major component of its sex pheromone. Previous isotope-labeling experiments demonstrated an unusual ∆12 desaturase activity involved in the biosynthesis of this compound; however, the putative ∆12 desaturase gene has not been reported to date. In the present study, we confirmed this ∆12 desaturation pathway by in vivo labeling experiments, and characterized candidate desaturase genes in a yeast heterologous expression system. We demonstrated that a pheromone gland-specific desaturase, SexiDes5, uses palmitic acid and the subsequently chain-shortened product (Z)-9-tetradecenoic acid as substrates to produce (Z)-11-hexadecenoic and (Z,E)-9,12-tetradecadienoic acids, respectively. In addition, the homologous desaturase SlitDes5 from the congeneric Spodoptera litura had analogous functions.

Sex Pheromones of Two Leafminer Species, Antispila oinophylla and Holocacista rivillei (Lepidoptera: Heliozelidae) Infesting Grapevine in Italy.

Two heliozelid species, Antispila oinophylla van Nieukerken & Wagner and Holocacista rivillei (Stainton) severely infest Italian grapevines. The volatile pheromones from calling females were collected by solid phase micro extraction (SPME) and analyzed by gas chromatography with electroantennographic detection (GC-EAD). Two compounds from A. oinophylla females eliciting electrophysiological activity from the conspecific male antenna were identified as (Z)-5-tetradecenal and (Z)-7-tetradecenal by coupled gas chromatography/mass spectrometry (GC/MS) analysis. SPME collections from H. rivillei produced no GC-EAD active compounds but analysis of fatty acyl moieties in the pheromone gland, demonstrated the presence of the putative pheromone biosynthetic precursors (Z)-5-dodecenoic acid and (Z)-7-tetradecenoic acid. Field trapping experiments in Italy confirmed that (Z)-5-tetradecenal and (Z)-7-tetradecenal are essential for the attraction of male A. oinophylla in a blend ratio of 15:100 respectively, whereas (Z)-5-dodecenal and (Z)-7-tetradecenal attract male H. rivillei in a blend ratio of 100:6.

Sterol O-acyltransferase 1 deficiency improves defective insulin signaling in the brains of mice fed a high-fat diet.

Insulin resistance induced by a high-fat diet (HFD) is related to metabolic diseases, and sterol O-acyltransferase 1 (SOAT1) is a key enzyme for the biosynthesis of cholesteryl ester. In the present study, wild-type (WT) mice and SOAT1-knockout (KO) mice with a C57BL6 background fed a HFD were used to explore the role of SOAT1 in the hypothalamus. The results show that the WT mice exhibited a significant increase in body weight as well as hepatic histologic changes; they also had a lower glucose and insulin tolerance than the WT mice fed a normal diet. However, the metabolic syndrome was attenuated in the SOAT1-KO HFD-fed mice. With regard to brain function, the SOAT1-KO HFD-fed mice showed improved cognitive function; they also manifested reduced levels of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and IL-6, which would otherwise be raised by a HFD. In addition, the HFD led to the overexpression of GFAP and phosphorylated NF-κB in the hypothalamus, changes that were reversed in the SOAT1-KO HFD-fed mice. Moreover, SOAT1-KO mice improved HFD-caused defective hypothalamic insulin resistance, as evidenced by the upregulation of p-insulin receptor (INSR), p-AKT and p-glycogen synthase kinase (GSK)-3ß, while the downregulation of p-AMP-activated protein kinase (AMPK)-α and p-acetyl-CoA carboxylase (ACC)-α. In addition, similar results were observed in high fructose (HFR)-stimulated astrocytes (ASTs) isolated from WT or KO mice. These results suggest that SOAT1 plays an important role in hypothalamic insulin sensitivity, linked to cognitive impairment, in HFD-fed mice.

Fatty acid profiles of great tit (Parus major) eggs differ between urban and rural habitats, but not between coniferous and deciduous forests.

Early-life nutrition is an important determinant of both short- and long-term performance and fitness. The avian embryo develops within an enclosed package of nutrients, of which fatty acids (FA) are essential for many aspects of development. The FA composition of yolk depends on maternal nutrition and condition prior to egg formation, which may be affected by the external environment. To test if maternal environment affects yolk FA composition, we investigated whether the FA composition of great tit (Parus major) egg yolks differed between urban and rural habitats, and between deciduous and coniferous habitats. The results reveal differences in FA composition between eggs laid in urban and rural habitats, but not between eggs from the coniferous and deciduous habitats. To a large extent, this difference likely reflects dietary differences associated with urban habitats rather than dominating vegetation type. Specifically, urban yolks contained lower proportions of both ω-3 and ω-6 polyunsaturated FAs (PUFA), which are important for chick development. We also found a positive association between the proportion of saturated fatty acids and laying date, and a negative association between the proportion of ω-6 PUFA and clutch size. Given that urbanization is expanding rapidly, future studies should investigate whether factors such as anthropogenic food in the urban environment underlie these differences and whether they impair chick development.

Characteristics of the water-soluble components of aerosol particles in Hefei, China.

Size-classified daily aerosol mass concentrations and concentrations of water-soluble inorganic ions were measured in Hefei, China, in four representative months between September 2012 and August 2013. An annual average mass concentration of 169.09 µg/m(3) for total suspended particulate (TSP) was measured using an Andersen Mark-II cascade impactor. The seasonal average mass concentration was highest in winter (234.73 µg/m(3)) and lowest in summer (91.71 µg/m(3)). Water-soluble ions accounted for 59.49%, 32.90%, 48.62% and 37.08% of the aerosol mass concentration in winter, spring, summer, and fall, respectively, which indicated that ionic species were the primary constituents of the atmospheric aerosols. The four most abundant ions were NO3(-), SO4(2-), Ca(2+) and NH4(+). With the exception of Ca(2+), the mass concentrations of water-soluble ions were in an intermediate range compared with the levels for other Chinese cities. Sulfate, nitrate, and ammonium were the dominant fine-particle species, which were bimodally distributed in spring, summer and fall; however, the size distribution became unimodal in winter, with a peak at 1.1-2.1 µm. The Ca(2+) peak occurred at approximately 4.7-5.8 µm in all seasons. The cation to anion ratio was close to 1.4, which suggested that the aerosol particles were alkalescent in Hefei. The average NO3(-)/SO4(2-) mass ratio was 1.10 in Hefei, which indicated that mobile source emissions were predominant. Significant positive correlation coefficients between the concentrations of NH4(+) and SO4(2-), NH4(+) and NO3(-), SO4(2-) and NO3(-), and Mg(2+) and Ca(2+) were also indicated, suggesting that aerosol particles may be present as (NH4)2SO4, NH4HSO4, and NH4NO3.

Identification of the Female-Produced Sex Pheromone of the Leafminer Holocacista capensis Infesting Grapevine in South Africa.

We report the first identification of a sex pheromone in a heliozelid moth, Holocacista capensis van Nieukerken & Geertsema. This leafminer recently infested grapevine in South Africa. Compared to solvent extraction of pheromone glands, solid phase microextraction (SPME) proved to be highly effective for collection of the pheromone from calling females. The volatiles collected by SPME were analyzed by gas chromatography with electroantennographic detection (GC/EAD). Three compounds eliciting electrophysiological activity from the male antenna were identified as (Z)-5-tetradecenal, (Z)-7-tetradecenal, and (Z)-9-hexadecenal by coupled gas chromatography-mass spectrometry (GC/MS). GC/MS analysis of dimethyldisulphide (DMDS) derivatives of fatty acyl moieties in pheromone gland extracts confirmed the presence of the corresponding putative pheromone precursors with double bonds in the same position and with Z geometry. Field trapping experiments in a South African vineyard confirmed that both (Z)-5-tetradecenal and (Z)-7-tetradecenal are essential for the attraction of male H. capensis, whereas addition of (Z)-9-hexadecenal to the blend did not affect the attractiveness. The composition of the pheromone is discussed in relation to the phylogeny of this family of moths.

Application of Intravascular Ultrasound in the Emergency Diagnosis and Treatment of Patients with ST-Segment Elevation Myocardial Infarction.

PURPOSE: This study aimed to examine the application of intravascular ultrasound (IVUS) in ST-segment elevation myocardial infarction (STEMI) patients with high thrombus burden (thrombus grade ≥3) undergoing emergency diagnosis and primary percutaneous coronary intervention. METHODS: Eighty STEMI patients were enrolled and randomly assigned to the IVUS-guided group (38 patients) or non-IVUS group (42 patients). Stent implantation was performed in non-IVUS group patients. IVUS group patients were further divided into low-risk and high-risk patients on the basis of IVUS evaluation for determining whether stenting should be performed. Major adverse cardiac event (MACE) rates, changes in the left ventricular end-diastolic diameter (LVEDD) and ejection fraction (EF) values, and stent numbers were examined during hospitalization, and follow-up was performed at 1, 3, 6, and 12 months postoperatively. RESULTS: During hospitalization, there were no significant differences in the MACE rates, LVEDD, and EF values and in the follow-up outcomes at 1, 3, 6, and 12 months postoperatively among the patients in the 2 groups (P > 0.05). A significantly lower number of stents were implanted in the IVUS group than in the non-IVUS group patients (P < 0.05). CONCLUSION: During the IVUS-guided emergency intervention, enhanced antithrombotic therapy and best medical care for low-risk STEMI patients may be feasible.

Sox17 inhibits hepatocellular carcinoma progression by downregulation of KIF14 expression.

Sox17, an antagonist of canonical Wnt/ß-catenin signaling, inhibits several malignant carcinogenesis and progression. However, little is known about Sox17 in hepatocellular carcinoma (HCC). Here, we found that Sox17 is downregulated in HCC tissue. Furthermore, Sox17 inhibits cell proliferation and migration in HCC. KIF14, a member of kinesin superfamily protein (KIFs), is an oncogene in a variety of malignant tumors including HCC. We demonstrated that Sox17 is negatively related to KIF14 expression in HCC tissue and Sox17 inhibits HCC cell proliferation and migration by transcriptional downregulation of KIF14 expression. Our results may provide a strategy for blocking HCC carcinogenesis and progression.

Identification and biosynthesis of novel male specific esters in the wings of the tropical butterfly, Bicyclus martius sanaos.

Representatives of the highly speciose tropical butterfly genus Bicyclus (Lepidoptera: Nymphalidae) are characterized by morphological differences in the male androconia, a set of scales and hair pencils located on the surface of the wings. These androconia are assumed to be associated with the release of courtship pheromones. In the present study, we report the identification and biosynthetic pathways of several novel esters from the wings of male B. martius sanaos. We found that the volatile compounds in this male butterfly were similar to female-produced moth sex pheromones. Components associated with the male wing androconial areas were identified as ethyl, isobutyl and 2-phenylethyl hexadecanoates and (11Z)-11-hexadecenoates, among which the latter are novel natural products. By topical application of deuterium-labelled fatty acid and amino acid precursors, we found these pheromone candidates to be produced in patches located on the forewings of the males. Deuterium labels from hexadecanoic acid were incorporated into (11Z)-11-hexadecenoic acid, providing experimental evidence of a Δ11-desaturase being active in butterflies. This unusual desaturase was found previously to be involved in the biosynthesis of female-produced sex pheromones of moths. In the male butterflies, both hexadecanoic acid and (11Z)-11-hexadecenoic acid were then enzymatically esterified to form the ethyl, isobutyl and 2-phenylethyl esters, incorporating ethanol, isobutanol, and 2-phenylethanol, derived from the corresponding amino acids L-alanine, L-valine, and L-phenylalanine.

Identification, synthesis, and behavioral activity of 5,11-dimethylpentacosane, a novel sex pheromone component of the greater wax moth, Galleria mellonella (L.).

The greater wax moth, Galleria mellonella (L.), is a serious and widespread pest of the honeybee, Apis mellifera L. In contrast to most moths, for which long-range mate finding is mediated by female-produced sex pheromones, G. mellonella males attract conspecific females over long distances by emitting large amounts of a characteristic scent in combination with bursts of ultrasonic calls. The male scent for this species was previously identified as a blend of nonanal and undecanal. When these compounds were bioassayed, characteristic short-range sexual behavior, including wing fanning, was triggered in conspecific females, but the aldehyde blend failed to elicit attraction over longer distances. We identified, via analysis and synthesis, a third male-specific compound, 5,11-dimethylpentacosane. We show that it acts as a behavioral synergist to the aldehydes. In wind tunnel experiments, very few female moths responded to the aldehyde blend or to 5,11-dimethylpentacosane tested separately, but consistently showed orientation and source contact when a combination of all three compounds was applied. The level of attraction to the three-component mixture was still lower than that to male extract, indicating that the composition of compounds in the synthetic blend is suboptimal, or that additional pheromone components of G. mellonella are yet to be identified. The identification of 5,11-dimethylpentacosane is an important step for the development of an efficient long-range attractant that will be integrated with other environmentally safe strategies to reduce damage to beehives caused by wax moths.

Sex pheromone biosynthesis in the sugarcane borer Diatraea saccharalis: paving the way for biotechnological production.

BACKGROUND: The sugarcane borer Diatraea saccharalis (Lepidoptera) is a key pest on sugarcane and other grasses in the Americas. Biological control as well as insecticide treatments are used for pest management, but economic losses are still significant. The use of female sex pheromones for mating disruption or mass trapping in pest management could be established for this species, provided that economical production of pheromone is available. RESULTS: Combining in vivo labelling studies, differential expression analysis of transcriptome data and functional characterisation of insect genes in a yeast expression system, we reveal the biosynthetic pathway and identify the desaturase and reductase enzymes involved in the biosynthesis of the main pheromone component (9Z,11E)-hexadecadienal, and minor components hexadecanal, (9Z)-hexadecenal and (11Z)-hexadecenal. We next demonstrate heterologous production of the corresponding alcohols of the pheromone components, by expressing multiple steps of the biosynthetic pathway in yeast. CONCLUSION: Elucidation of the genetic basis of sex pheromone biosynthesis in D. saccharalis, and heterologous expression in yeast, paves the way for biotechnological production of the pheromone compounds needed for pheromone-based pest management of this species. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.