Main Pheromone Component Research Articles

Novel (E)-β-Farnesene Analogues Containing 2-Nitroiminohexahydro-1,3,5-triazine: Synthesis and Biological Activity Evaluation.

In order to discover novel eco-friendly compounds with good activity for aphid control, (E)-β-farnesene (EβF), the main component of the aphid alarm pheromone, was chosen as the lead compound. By introducing a 2-nitroimino-hexahydro-1,3,5-triazine moiety (abbreviated NHT) to replace the unstable conjugated double bond system of EβF, a series of novel EβF analogues containing the NHT moiety were synthesized via the reaction of substituted NHT rings with (E)-1-chloro-3,7-dimethylocta-2,6-diene. All the compounds were characterized by 1H-NMR, 13C-NMR, IR, and high resolution mass spectroscopy (HRMS). The bioassay results showed that all the analogues displayed different repellent and aphicidal activities against green peach aphid (Myzus persicae). Particularly, the analogue 4r exhibited obvious repellent activity (repellent proportion: 78.43%) and similar aphicidal activity against M. persicae (mortality: 82.05%) as the commercial compound pymetrozine (80.07%). A preliminary structure-activity relationship (SAR) study was also performed, which offered valuable clues for the design of further new EβF analogues.

Selective extraction of Bactrocera oleae sexual pheromone from olive oil by dispersive magnetic microsolid phase extraction using a molecularly imprinted nanocomposite

Bactrocera oleae Gmelin, also known as olive fruit fly, is the main olive tree pest. It produces a severe effect not only on the productivity but also on the quality of the olive-related products. In fact, the oil obtained from infected olives has a lower antioxidant power. In addition, an increase of the oil acidity, peroxide index and UV-absorbance can also be observed. 1,7-dioxaspiro-[5,5]-undecane (DSU), is the main component of the sexual pheromone of this pest and may be used as marker of the pest incidence. In this context, the development of new methods able to detect the pheromones in several samples, including agri-food or environmental ones, is interesting. In this work, we synthesized a molecularly imprinted polymer (MIPS) layer over magnetic nanoparticles (Fe3O4@SiO2@MIP) for the selective recognition of DSU. They were prepared using DSU as template and 3-aminopropyltriethoxysilane (APTES) to associate the target analyte on the surface of the magnetic substrate and the later polymerization of ethylene glycol dimethacrylate (EGDMA) in presence of 2,2-azobisisobutyonnitrile (AIBN). The resulting Fe3O4@SiO2@MIP composite was characterized by different techniques. The maximum adsorption capacity of DSU on Fe3O4@SiO2@MIP in hexane was 32mg/g (5.3 times than that obtained for the non-imprinted composite). In addition, Fe3O4@SiO2@MIP showed a short equilibrium time (45min) and potential reusability. The combination of dispersive magnetic microsolid phase extraction and gas chromatography with mass spectrometric detection allows the determination of DSU in real samples at concentrations as low as 10μg/L with precision better than 7.5% (expressed as relative standard deviation). The relative recoveries are in the range between 95 and 99%, which indicates the potential of the methodology. Finally, it has been applied to real olive oil samples being the presence of the pest detected is some of them.

A herbivore-induced plant volatile interferes with host plant and mate location in moths through suppression of olfactory signalling pathways.

BackgroundPlants under herbivore attack release volatiles that attract natural enemies, and herbivores in turn avoid such plants. Whilst herbivore-induced plant volatile blends appeared to reduce the attractiveness of host plants to herbivores, the volatiles that are key in this process and particularly the way in which deterrence is coded in the olfactory system are largely unknown. Here we demonstrate that herbivore-induced cotton volatiles suppress orientation of the moth Spodoptera littoralis to host plants and mates.ResultsWe found that (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), an induced volatile, is key in herbivore deterrence: DMNT suppressed plant odour- and pheromone-induced behaviours. We then dissected the neurophysiological basis of this interaction. DMNT-responding glomeruli were also activated by other plant compounds, suggesting that S. littoralis possesses no segregated olfactory circuit dedicated exclusively to DMNT. Instead, DMNT suppressed responses to the main pheromone component, (Z)-9-(E)-11-tetradecenyl acetate, and primarily to (Z)-3-hexenyl acetate, a host plant attractant.ConclusionOur study shows that olfactory sensory inhibition, which has previously been reported without reference to an animal’s ecology, can be at the core of coding of ecologically relevant odours. As DMNT attracts natural enemies and deters herbivores, it may be useful in the development or enhancement of push-pull strategies for sustainable agriculture.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-015-0188-3) contains supplementary material, which is available to authorized users.

Artificial night lighting disrupts sex pheromone in a noctuid moth

1. One major, yet poorly studied, change in the environment is the increase in nocturnal light pollution. Although this strongly alters the habitat of nocturnal species, the ecological consequences are poorly known. Moths are well known to be attracted to artificial light sources, but artificial light may affect them in other ways as well.2. In this study, female Mamestra brassicae moths were subjected to various types of low‐intensity artificial night lighting with contrasting spectral compositions (green‐rich, red‐rich, warm white) or to a dark control treatment and the effects on their sex pheromone production and composition were tested.3. Artificial night lighting reduced sex pheromone production and altered the chemical composition of the pheromone blend, irrespective of spectral composition. Specifically, amounts of the main pheromone component Z11‐16:Ac were reduced, while the deterring compounds Z9‐14:Ac, Z9‐16:Ac, and Z11‐16:OH were increased relative to Z11‐16:Ac when females were kept under artificial light. These changes may reduce the effectiveness of the sex pheromones, becoming less attractive for males.4. These results show for the first time that artificial light at night affects processes that are involved in moth reproduction. The potential for mitigation through manipulation of the spectral composition of artificial light appears limited.

The regulation of Δ11-desaturase gene expression in the pheromone gland of Mamestra brassicae (Lepidoptera; Noctuidae) during pheromonogenesis

Cabbage moth (Mamestra brassicae) females produce sex pheromones to attract conspecific males. In our M. brassicae colony, the pheromone blend is composed of Z11-hexadecenyl acetate (Z11-16Ac) and hexadecyl acetate (16Ac) in a 93:7 ratio. A fatty acyl Δ11-desaturase is involved in the production of the main pheromone component. The release of Pheromone Biosynthesis Activating Neuropeptide (PBAN) regulates the pheromone production in the pheromone gland (PG).We cloned a cDNA encoding the MambrΔ11-desaturase and analyzed its expression profile over time in M. brassicae tissues. Transcript levels of the Δ11-desaturase in larvae, pupal PGs, fat body, brain and muscle tissues were <0.1% of that in female PGs, whereas expression in male genitalia was 2%. In the PGs of virgin females the expression level increased continuously from eclosion to the end of the 1st day when it reached a plateau without further significant fluctuation up to the 8th day. In contrast, we recorded a characteristic daily rhythmicity in pheromone production with a maximum around 200ng Z11-16Ac/PG. In some experiments, females were decapitated to prevent PBAN release and thereby inhibit pheromone production, which remarkably increased after treatment with Mambr-Pheromonotropin. Further experiments revealed that mating resulted in a significant suppression of pheromone production. However, expression of the Δ11-desaturase was not affected by any of these interventions, suggesting that it’s not regulated by PBAN. Fluorescent microscopy was used to study the potential role of lipid droplets during pheromone production, however, no lipid droplets were identified indicating that pheromonogenesis is regulated via de novo fatty acid synthesis.

Heterogeneity and convergence of olfactory first-order neurons account for the high speed and sensitivity of second-order neurons.

In the olfactory system of male moths, a specialized subset of neurons detects and processes the main component of the sex pheromone emitted by females. It is composed of several thousand first-order olfactory receptor neurons (ORNs), all expressing the same pheromone receptor, that contact synaptically a few tens of second-order projection neurons (PNs) within a single restricted brain area. The functional simplicity of this system makes it a favorable model for studying the factors that contribute to its exquisite sensitivity and speed. Sensory information—primarily the identity and intensity of the stimulus—is encoded as the firing rate of the action potentials, and possibly as the latency of the neuron response. We found that over all their dynamic range, PNs respond with a shorter latency and a higher firing rate than most ORNs. Modelling showed that the increased sensitivity of PNs can be explained by the ORN-to-PN convergent architecture alone, whereas their faster response also requires cell-to-cell heterogeneity of the ORN population. So, far from being detrimental to signal detection, the ORN heterogeneity is exploited by PNs, and results in two different schemes of population coding based either on the response of a few extreme neurons (latency) or on the average response of many (firing rate). Moreover, ORN-to-PN transformations are linear for latency and nonlinear for firing rate, suggesting that latency could be involved in concentration-invariant coding of the pheromone blend and that sensitivity at low concentrations is achieved at the expense of precise encoding at high concentrations.

Some Personal Recollections of Pheromone Research in Australia in the 1970s

The Journal of Chemical Ecology, particularly in its early years was devoted almost exclusively to research on pheromones. In the 1970s, considerable advances were being made in understanding the mechanisms underlying pheromone-mediated behavior, particularly in laboratory environments (e.g. R.J. Bartell at CSIRO Australia), as well as the chemical characterization of pheromones and recognizing the importance of minor components. However, there was little ecologically-based research at that time on the impacts of modifying pheromone-mediated behavior on the population dynamics of target pests, particularly in terms of validating the quantitative contributions of mating disruption or mass trapping to pest abundance within and between seasons. Among several reasons for this was that few sex pheromones of lepidopteran pests had been characterized and synthesised. However, in 1969, Wendell Roelofs published the identity of the main component of the female sex pheromone of a major moth pest with pan-continental distribution, the oriental fruit moth (OFM: Cydia (Grapholitha) molesta (Busck)), as cis-8 dodecenyl acetate, recognizing from field assays that there were probably also uncharacterized secondary components. This breakthrough enabled the group at CSIRO Australia to begin larger scale field work, although there were initially challenges in getting sufficient quantities of synthetic pheromone. As an aside, there was evidence from early CSIRO field tests that the far cheaper saturated analogue, dodecyl acetate, inhibited males from being attracted to live females or synthetic pheromone sources, but when extremely high background doses were released in a larger field trial, trap captures of males actually went up—all reflecting the lack of understanding of underlying mechanisms. Later research revealed that dodecyl acetate is a component of the female pheromone blend.

Studies on the Codling Moth (Lepidoptera: Tortricidae) Response to Different Codlemone Release Rates

The response of the codling moth (Cydia pomonella L. (Lepidoptera: Tortricidae)) to different emission values of its main pheromone component, 8E,10E-dodecadien-1-ol (codlemone), was investigated in three field trials conducted in plots without mating disruption treatments. Moth catches obtained in traps baited with pheromone dispensers were correlated with the corresponding codlemone release rates by multiple regression analysis. In a preliminary trial conducted in Lleida (NE Spain), a decreasing trend of captures was observed based on increasing pheromone levels. After this, the pheromone release profiles of the pheromone dispensers were studied, in parallel with the field trials, by residual codlemone extraction and gas chromatography quantification. In the trials carried out in Asturias (NW Spain), a correlation between trap catches and emission levels (within the range from 11 to 1,078 μg/d) was found and fitted a logarithmic model. Captures followed a decreasing linear trend in the range of emission rates from 11 to 134 μg/d. Given that release values comprised between 11 and 67 μg/d did not lead to significantly different catches in traps, this emission range could be considered to develop effective formulations for attraction purposes when mating disruption is not acting in the environment.

A nonspecific defensive compound evolves into a competition avoidance cue and a female sex pheromone

The evolution of chemical communication and the origin of pheromones are among the most challenging issues in chemical ecology. Current theory predicts that chemical communication can arise from compounds primarily evolved for non-communicative purposes but experimental evidence showing a gradual evolution of non-informative compounds into cues and true signals is scarce. Here we report that females of the parasitic wasp Leptopilina heterotoma use the defensive compound (−)-iridomyrmecin as a semiochemical cue to avoid interference with con- and heterospecific competitors and as the main component of a species-specific sex pheromone. Although competition avoidance is mediated by (−)-iridomyrmecin alone, several structurally related minor compounds are necessary for reliable mate attraction and recognition. Our findings provide insights into the evolution of insect pheromones by demonstrating that the increasing specificity of chemical information is accompanied by an increasing complexity of the chemical messengers involved and the evolution of the chemosensory adaptations for their exploitation.

Disruption of Phthorimaea operculella (Lepidoptera: Gelechiidae) oviposition by the application of host plant volatiles.

BACKGROUNDPhthorimaea operculella is a key pest of potato. The authors characterised the P. operculella olfactory system, selected the most bioactive host plant volatiles and evaluated their potential application in pest management. The electrophysiological responses of olfactory receptor neurons (ORNs) housed in long sensilla trichodea of P. operculella to plant volatiles and the two main sex pheromone components were evaluated by the single-cell recording (SCR) technique. The four most SCR-active volatiles were tested in a laboratory oviposition bioassay and under storage warehouse conditions.RESULTSThe sensitivity of sensilla trichodea to short-chained aldehydes and alcohols and the existence of ORNs tuned to pheromones in females were characterised. Male recordings revealed at least two types of ORN, each of which typically responded to one of the two pheromone components. Hexanal, octanal, nonanal and 1-octen-3-ol significantly disrupted the egg-laying behaviour in a dose-dependent manner. Octanal reduced the P. operculella infestation rate when used under storage conditions.CONCLUSIONSThis work provides new information on the perception of plant volatiles and sex pheromones by P. operculella. Laboratory and warehouse experiments show that the use of hexanal, octanal, nonanal and 1-octen-3-ol as host recognition disruptants and/or oviposition deterrents for P. operculella control appears to be a promising strategy. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

More than a pest management tool — 45 years of practical experience with insect pheromones in stored-product and material protection

The application of pheromone-baited traps to control pest insects in stored food or materials has become well established over the past decades. The main pheromone components of all major stored-product and material pests have been identified. Pest monitoring with pheromone traps is a key factor in integrated pest management to estimate population density build-ups and they may be used to define economic threshold levels. Male-attracting sex pheromones, e.g. for stored-product pyralids, the clothes moths, and some anobiid beetles, are especially effective in this aspect. Monitoring pest population can facilitate optimal spatial and temporal control strategies, including efficacy evaluation of the implemented control measures. In addition to the sex pheromones, some beetles, such as grain and flour beetles, utilize aggregation pheromones, which attract both sexes. Implementation of these pheromones for mass trapping, which works well for the control of bark beetles in the forest environment, has been less successful for stored-product protection for various reasons and is thus not an established means of control. When the monitoring tools are used in landscape areas, scrublands, forests, and away from anthropogenic influenced environments, natural reservoirs of a pest species and sources of new infestations can be identified. In addition to an economically driven adoption of pheromone traps, they may also provide information of a pest’s general biology. Because stored-product and material pests must be considered neozoons in most parts of the world, their occurrence in natural habitats indicates a species’ autecological capability to successfully compete with native species and to become fau-nistically established in non-synanthropic environments outside their zoogeographic origin. This review focuses on the use of pheromone traps for monitoring in outdoor situations.

Effect of post‐teneral diets on the performance of sterileAnastrepha ludensandAnastrepha obliquafruit flies

AbstractThe effect of post‐teneral diets on the mating performance, pheromone production and longevity of sterileAnastrepha ludensandAnastrepha obliquafruit flies (Diptera: Tephritidae) was investigated. Enriched pre‐release diets improved male mating performance. Wild and sterile males fed on mango and orange fruits achieved the greatest copulatory success, followed by those fed on a 3 : 1 sugar : yeast (SY) diet. Males fed only on a sugar diet achieved the lowest number of matings. The mean numbers of copulas achieved by wild males were significantly higher than those by sterile males fed on a sugar‐only diet, while there were no significant differences between wild males and sterile males fed on yeast diets. There was a trend of reduced mean number of copulas as the proportion of yeast was reduced in the diet, but differences were not significant. Pre‐release diets had a significant effect on pheromone production. Males fed on a 3 : 1 SY diet produced the greatest amount of the three main pheromone components inA. ludensmales and two major components inA. obliquamales, followed by males fed on fruits or pasteurized fruit juice. Males fed on a sugar only diet produced the lowest amounts. The longevity response to post‐teneral diets was complex. The most yeast‐rich diet and the poorest diet (sugar only) resulted in the lowest life expectancies. Flies fed on 24 : 1 SY diets showed the highest life expectancies for both males and females of the two species. Considering the tradeoffs between mating performance and longevity, the 24 : 1 SY diet would be recommended for programmes integrating the sterile insect technique, but the effects of these diets on field survival and dispersal still need to be investigated.

Behavioural and electrophysiological responses of the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), to male- and female-borne sex attractants

In the olive fruit fly, Bactrocera oleae, females attract males by producing 1,7-dioxaspiro[5.5]undecane (olean), the main component of the sex pheromone secreted by rectal glands. It has been recently demonstrated that males are able to produce (Z)-9-tricosene (muscalure) in rectal glands, a compound that selectively attracts females. In this study, a male grooming reaction that may transfer the male-borne compounds from rectal to urotergal glands was observed, suggesting that urotergal glands could be involved in B. oleae sexual communication. GC/MS, EAG, GC/EAD analyses and behavioural assays were carried out to compare the role of male rectal and urotergal glands during courtship. In both male glands, olean and muscalure amounts were age dependent. Extracts of rectal glands contained higher amounts of olean and/or muscalure than urotergal ones. Extracts of rectal and urotergal glands of males and females elicited EAG responses in both sexes. GC/EAD showed that female EAG response to male rectal extracts was mainly due to olean and muscalure. Synthetic compounds evoked EAG dose-dependent responses in both sexes, and the EAG response to muscalure was higher as compared to olean. Rectal and urotergal glands from old males were able to attract females, while urotergal glands from young males attracted only males. Overall, our results add knowledge to the mating system of B. oleae, giving first evidences on the electrophysiological activity of muscalure towards both sexes, as well as on the involvement of male urotergal glands in the chemical sexual communication of this pest.

The main component of an alarm pheromone of kissing bugs plays multiple roles in the cognitive modulation of the escape response

Innate responses in animals can be modulated by experience. Disturbed adults of the triatomine bug Triatoma infestans release an alarm pheromone (AP) that elicits an escape response in conspecific larvae. The main component of this AP, the isobutyric acid (IsoAc), alone has already shown to generate an escape response in this species. However, not much is known about the modulation of this behavior by non-associative and associative cognitive processes. We present here evidences of the cognitive capacities of T. infestans larvae in an escape context under different conditioning paradigms, including IsoAc in different roles. We show that: (1) the duration of a pre-exposure to IsoAc plays a main role in determining the type of non-associative learning expressed: short time pre-exposures elicit a sensitization while a longer pre-exposure time triggers a switch from repellence to attractiveness; (2) a simple pre-exposure event is enough to modulate the escape response of larvae to the AP and to its main component: IsoAc; (3) IsoAc and the AP are perceived as different chemical entities; (4) an association between IsoAc and an aversive stimulus can be created under a classical conditioning paradigm; (5) an association between IsoAc and a self-action can be generated under an operant conditioning. These results evince that IsoAc can attain multiple and different cognitive roles in the modulation of the escape response of triatomines and show how cognitive processes can modulate a key behavior for surviving, as it is the escaping response in presence of a potential danger in insects.

Facile Synthesis of (Z,E)-9,11-Hexadecadienal, the Major Sex Pheromone Component of the Sugarcane Borer Diatraea saccharalis: An Efficient Strategy for Synthesis of (Z,E)-Dienic Pheromones

Practical and improved procedures for the synthesis of 7-bromo-(Z,E)-4,6-heptadienal by Pd(II)-catalyzed coupling reaction were developed. Based on the improved method, an efficient and stereoselective synthesis of (Z,E)-9,11-hexadecadienal, the main pheromone component of the sugarcane borer, Diatraea saccharalis, was achieved in 38% overall yield, which more desirable then previously reported methods. The stereochemistry relied on cross-coupling between Grignard reagent and protected 7-bromo-(Z,E)-4,6-heptadienal. The concise and facile synthetic strategy described herein provided a generally synthetic approach to other (Z,E)-dienic compounds.

Sex Pheromone of the Smaller Clearwing Moth Synanthedon tenuis (Butler)

The smaller clearwing moth, Synanthedon tenuis (Butler) (Lepidoptera: Sesiidae), is a major pest of persimmon in northeast Asia. A previous study reported attraction of S. tenuis males to Z3,Z13-18:OAc, but this compound had no effect on male catch in the persimmon orchards in Korea. In this study, we analyzed pheromone gland extracts of S. tenuis females and identified Z3,Z13-18:OH as the main component. In field trapping trial, Z3,Z13-18:OH alone was attractive to S. tenuis males and competitive with live virgin females. These results indicate that the pheromone of this species consists of a single component, Z3,Z13-18:OH. However, Z3,Z13-18:OAc, a previously reported attractant, was not detected in the gland extracts of females. Furthermore, the addition of Z3,Z13-18:OAc to the main pheromone component strongly inhibited attraction for males, suggesting that the diene acetate is not a pheromone component. This is the first report of an octadecadienol as female-produced sex pheromone from the genus Synanthedon.

Characterization of Epoxytrienes Derived from (3Z,6Z,9Z)-1,3,6,9-Tetraenes, Sex Pheromone Components of Arctiid Moths and Related Compounds

Cis-9,10-epoxy-(3Z,6Z)-1,3,6-henicosatriene has been identified from a pheromone gland of arctiid species, such as Hyphantria cunea. Since the diversity of lepidopteran species suggests that structurally related compounds of the 9,10-epoxide are also utilized as a sex pheromone components, epoxytrienes derived from (3Z,6Z,9Z)-1,3,6,9-tetraenes with a C(19)-C(21) chain were systematically synthesized and characterized. While 1,2-epoxy-3,6,9-triene was not obtained, peracid oxidation of each tetraene produced a mixture of three cis-epoxides (3,4-epoxy-1,6,9-triene, 6,7-epoxy-1,3,9-triene, and 9,10-epoxy-1,3,6-triene), which were separable by LC as well as GC. Detailed inspection of the mass spectra of the C(19)-C(21) epoxides indicated the following diagnostic ions for determining the chemical structures: m/z 79, M-70, and M-41 for the 3,4-epoxytrienes; m/z 79, 95, 109, and 149 for the 6,7-epoxytrienes; and m/z 79, 106, 120, M-121, and M-107 for the 9,10-epoxytrienes. Resolution of two enantiomers of each C(21) epoxytriene was accomplished by HPLC equipped with a chiral column, and analysis of the pheromone extracted from virgin females of H. cunea revealed the 9S,10R configuration of the natural epoxytriene as the same configuration of C(21) 9,10-epoxydiene, a main pheromone component of this species. GC-EAD analysis of the optically pure epoxides showed that the antennae of male H. cunea were stimulated more strongly (>100 times) by the (9S,10R)-isomers than the antipodes.

Experience-dependent modulation of antennal sensitivity and input to antennal lobes in male moths (Spodoptera littoralis) pre-exposed to sex pheromone

Sex pheromones are intraspecific olfactory signals emitted by one sex to attract a potential mating partner. Behavioural responses to sex pheromones are generally highly stereotyped. However, they can be modulated by experience, as male moths previously exposed to female sex pheromone respond with a lower threshold upon further detection, even after long delays. Here, we address the question of the neural mechanisms underlying such long-term modulation. As previous work has shown increased responses to pheromone in central olfactory neurons, we asked whether brief exposure to the pheromone increases input activity from olfactory receptor neurons. Males pre-exposed to sex pheromone exhibited increased peripheral sensitivity to the main pheromone component. Among nine antennal genes targeted as putatively involved in pheromone reception, one encoding a pheromone-binding protein showed significant upregulation upon exposure. In the primary olfactory centre (antennal lobe), the neural compartment processing the main pheromone component was enlarged after a brief pheromone exposure, thus suggesting enduring structural changes. We hypothesise that higher peripheral sensitivity following pre-exposure leads to increased input to the antennal lobe, thus contributing to the structural and functional reorganization underlying a stable change in behaviour.

Metabolic Engineering of Plant‐derived (E)‐β‐farnesene Synthase Genes for a Novel Type of Aphid‐resistant Genetically Modified Crop PlantsF

AbstractAphids are major agricultural pests that cause significant yield losses of crop plants each year. Excessive dependence on insecticides for long‐term aphid control is undesirable because of the development of insecticide resistance, the potential negative effects on non‐target organisms and environmental pollution. Transgenic crops engineered for resistance to aphids via a non‐toxic mode of action could be an efficient alternative strategy. (E)‐β‐Farnesene (EβF) synthases catalyze the formation of EβF, which for many pest aphids is the main component of the alarm pheromone involved in the chemical communication within these species. EβF can also be synthesized by certain plants but is then normally contaminated with inhibitory compounds. Engineering of crop plants capable of synthesizing and emitting EβF could cause repulsion of aphids and also the attraction of natural enemies that use EβF as a foraging cue, thus minimizing aphid infestation. In this review, the effects of aphids on host plants, plants’ defenses against aphid herbivory and the recruitment of natural enemies for aphid control in an agricultural setting are briefly introduced. Furthermore, the plant‐derived EβF synthase genes cloned to date along with their potential roles in generating novel aphid resistance via genetically modified approaches are discussed. image [ Lan‐Qin Xia (Corresponding author)]

New Technologies, Tools and Approaches for Improving Crop Breeding

New Technologies, Tools and Approaches for Improving Crop Breeding