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Farias LR, Paula DP, Zhou JJ, Liu R, Pappas GJ, Moraes MCB, Laumann RA, Borges M, Birkett MA, Pickett JA, Field LM, Báo SN. Identification and Expression Profile of Two Putative Odorant-Binding Proteins from the Neotropical Brown Stink Bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae). NEOTROPICAL ENTOMOLOGY 2014; 43:106-14. [PMID: 27193516 DOI: 10.1007/s13744-013-0187-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 12/02/2013] [Indexed: 06/05/2023]
Abstract
This work presents the first identification of putative odorant-binding proteins (OBPs) from a member of the Pentatomidae, i.e. the brown stink bug Euschistus heros (Fabricius), an important pest of soybean in Brazil. Antennae from both sexes of E. heros adults (12 days old and unmated) were used to construct a cDNA library, from which two transcripts encoding putative E. heros OBPs (EherOBPs) were identified. The expression levels of EherOBP1 and EherOBP2 were found to be higher in male antennae than in female and there was difference in expression in legs, wings, and abdomens of the two sexes. The histolocalization of EherOBP1 and EherOBP2 transcripts in antennae also showed a sexual dimorphism in the chemoreception system, with different expression sites in the antennal segments between males and females, occurring predominantly at the base of the sensillum. The implications of these findings for stink bug chemoreception are discussed.
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Elek H, Smart L, Ahmad S, Anda A, Werner CP, Pickett JA. A comparison of the levels of hydroxamic acids in Aegilops speltoides and a hexaploid wheat and effects on Rhopalosiphum padi behaviour and fecundity. ACTA BIOLOGICA HUNGARICA 2014; 65:38-46. [PMID: 24561893 DOI: 10.1556/abiol.65.2014.1.4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hydroxamic acids (HAs) are plant secondary metabolites produced by certain cereals, which have been found to be toxic to pest aphids in artificial diet assays. Previous studies have shown that tetraploid and hexaploid wheat varieties, the leaf tissues of which contained higher levels of these compounds than used in artificial diets, did not reduce aphid settling or fecundity. This current study reports findings on a high HA producing B genome accession of the diploid ancestor of wheat, Aegilops speltoides. We found that this accession does have a negative impact on aphid host selection and substantially reduces nymph production. Whole leaf tissue assays showed very high levels of HAs, well in excess of the toxic level determined in the artificial diet assays. Extraction of the apoplast fluid (AF) from this accession showed that the HA level is much lower than that of the whole tissue, but is still close to the artificial diet toxic level. Furthermore the HA level in the AF increases in response to aphid feeding. These observations could explain why hexaploid wheat remains susceptible to aphids, despite having whole leaf tissue HA levels in excess of the toxic levels determined in artificial diets.
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Poppy GM, Jepson PC, Pickett JA, Birkett MA. Achieving food and environmental security: new approaches to close the gap. Philos Trans R Soc Lond B Biol Sci 2014; 369:20120272. [PMID: 24535384 DOI: 10.1098/rstb.2012.0272] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Pickett JA, Aradottír GI, Birkett MA, Bruce TJA, Hooper AM, Midega CAO, Jones HD, Matthes MC, Napier JA, Pittchar JO, Smart LE, Woodcock CM, Khan ZR. Delivering sustainable crop protection systems via the seed: exploiting natural constitutive and inducible defence pathways. Philos Trans R Soc Lond B Biol Sci 2014; 369:20120281. [PMID: 24535389 DOI: 10.1098/rstb.2012.0281] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To reduce the need for seasonal inputs, crop protection will have to be delivered via the seed and other planting material. Plant secondary metabolism can be harnessed for this purpose by new breeding technologies, genetic modification and companion cropping, the latter already on-farm in sub-Saharan Africa. Secondary metabolites offer the prospect of pest management as robust as that provided by current pesticides, for which many lead compounds were, or are currently deployed as, natural products. Evidence of success and promise is given for pest management in industrial and developing agriculture. Additionally, opportunities for solving wider problems of sustainable crop protection, and also production, are discussed.
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Pickett JA, Woodcock CM, Midega CAO, Khan ZR. Push-pull farming systems. Curr Opin Biotechnol 2014; 26:125-32. [PMID: 24445079 DOI: 10.1016/j.copbio.2013.12.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 12/11/2013] [Accepted: 12/12/2013] [Indexed: 12/16/2022]
Abstract
Farming systems for pest control, based on the stimulo-deterrent diversionary strategy or push-pull system, have become an important target for sustainable intensification of food production. A prominent example is push-pull developed in sub-Saharan Africa using a combination of companion plants delivering semiochemicals, as plant secondary metabolites, for smallholder farming cereal production, initially against lepidopterous stem borers. Opportunities are being developed for other regions and farming ecosystems. New semiochemical tools and delivery systems, including GM, are being incorporated to exploit further opportunities for mainstream arable farming systems. By delivering the push and pull effects as secondary metabolites, for example, (E)-4,8-dimethyl-1,3,7-nonatriene repelling pests and attracting beneficial insects, problems of high volatility and instability are overcome and compounds are produced when and where required.
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81
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Williams IH, Pickett JA, Martin AP. The Nasonov pheromone of the honeybeeApis mellifera L. (Hymenoptera, Apidae). Part II. Bioassay of the components using foragers. J Chem Ecol 2014; 7:225-37. [PMID: 24420468 DOI: 10.1007/bf00995745] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/1980] [Revised: 05/20/1980] [Indexed: 11/30/2022]
Abstract
The Nasonov pheromone of the honeybee comprises seven components, (Z)-citral, nerol, geraniol, nerolic acid, geranic acid, and (E,E)-farnesol. Bioassay of individual components showed each attracted foraging bees. A mixture of components in proportions present in the honeybee was as attractive as the natural secretion, and each component contributed to the attractiveness of the mixture. Honeybees responded anemotactically to the source of Nasonov odor. The presence of footprint pheromone enhanced the attractiveness of the synthetic Nasonov mixture. Nasonov and footprint pheromones may prove useful in attracting honeybees to crops needing pollination.
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Pickett JA, Williams IH, Smith MC, Martin AP. Nasonov pheromone of the honey bee,Apis mellifera L. (Hymenoptera, Apidae). part III. : Regulation of pheromone composition and production. J Chem Ecol 2014; 7:543-54. [PMID: 24420593 DOI: 10.1007/bf00987702] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/1980] [Revised: 08/19/1980] [Indexed: 11/27/2022]
Abstract
GC and GC-MS analyses of the multicomponent Nasonov pheromone of the honey bee, and of the air above insects releasing the pheromone, show that constant composition is maintained during release, despite differing volatilities of the components. The regulating mechanism may involve a specific enzyme process, detected in excised Nasonov glands, which converts the major component geraniol into the more volatile (E)-citral. Analysis of honey bees of known ages and at different times of year shows that maximum secretion occurs when foraging is most likely.
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Williams IH, Pickett JA, Martin AP. Nasonov pheromone of the honeybee.Apis mellifera L. (Hymenoptera, Apidae) : IV. Comparative electroantennogram responses. J Chem Ecol 2014; 8:567-74. [PMID: 24414967 DOI: 10.1007/bf00987804] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/1981] [Revised: 07/28/1981] [Indexed: 10/26/2022]
Abstract
Electroantennogram (EAG) responses from worker honeybee antennae were obtained for each Nasonov component. Response amplitudes to 10 μg of components correlated well with reported relative abilities to attract foragers in the field. EAG responses of worker, queen, and drone antennae to natural pheromone were consistently greater than to synthetic pheromone, a difference only partly explained by enzymic conversion of geraniol to (E)-citral during preparation of natural extracts.
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84
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Dawson GW, Mudd A, Pickett JA, Pile MM, Wadhams LJ. Convenient synthesis of mosquito oviposition pheromone and a highly fluorinated analog retaining biological activity. J Chem Ecol 2013; 16:1779-89. [PMID: 24263984 DOI: 10.1007/bf01020494] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/1989] [Accepted: 02/12/1990] [Indexed: 10/25/2022]
Abstract
A simple three-step synthesis is described for 6-acetoxy-5-hexadecanolide, the oviposition pheromone of the mosquitoCulex quinquefasciatus Say and others in that genus. An aldol condensation between 1-trimethylsilyloxycyclopent-1-ene and undecanal, followed by Baeyer-Villiger ring expansion and acetylation, gave the required compound as a 1∶1 mixture of diastereoisomers in high overall yield (>80%). This synthetic approach is readily adapted for synthesis of analogs. The heptadecafluoro compound, in which then-octyl group is replaced by perfluorooctyl, retained high biological activity.
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Blight MM, Pickett JA, Wadhams LJ, Woodcock CM. Antennal perception of oilseed rape,Brassica napus (Brassicaceae), volatiles by the cabbage seed weevilCeutorhynchus assimilis (Coleoptera, Curculionidae). J Chem Ecol 2013; 21:1649-64. [PMID: 24233820 DOI: 10.1007/bf02033667] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/1995] [Accepted: 07/08/1995] [Indexed: 10/25/2022]
Abstract
The response of theCeutorhynchus assimilis antenna to volatiles in air entrainment-derived extracts of oilseed rape,Brassica napus, was studied using coupled gas chromatography (GC)-electroantennography (EAG) and coupled GC-single cell recording (SCR). By means of these techniques and coupled gas chromatography-mass spectrometry (GC-MS), 25 active compounds were identified, including isoprenoids and compounds derived from fatty acids and amino acids. Some of the latter, the isothiocyanates and goitrin, and probably indole and benzyl cyanide, are catabolites of glucosinolates. The electrophysiological activity of the identified compounds was confirmed by EAG using a physiologically discriminating dose, and by SCR studies. The importance of the combined use of the EAG and SCR techniques was demonstrated, since specific olfactory cells were located for five compounds that did not elicit significant EAG responses. The majority of the olfactory cells from which single cell recordings were obtained showed very high specificity, and in numerous recordings there were consistent pairings of specific cell types.
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86
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Babikova Z, Gilbert L, Bruce T, Dewhirst SY, Pickett JA, Johnson D. Arbuscular mycorrhizal fungi and aphids interact by changing host plant quality and volatile emission. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12181] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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87
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Gu SH, Wu KM, Guo YY, Pickett JA, Field LM, Zhou JJ, Zhang YJ. Identification of genes expressed in the sex pheromone gland of the black cutworm Agrotis ipsilon with putative roles in sex pheromone biosynthesis and transport. BMC Genomics 2013; 14:636. [PMID: 24053512 PMCID: PMC3849270 DOI: 10.1186/1471-2164-14-636] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 09/13/2013] [Indexed: 11/26/2022] Open
Abstract
Background One of the challenges in insect chemical ecology is to understand how insect pheromones are synthesised, detected and degraded. Genome wide survey by comparative sequencing and gene specific expression profiling provide rich resources for this challenge. A. ipsilon is a destructive pest of many crops and further characterization of the genes involved in pheromone biosynthesis and transport could offer potential targets for disruption of their chemical communication and for crop protection. Results Here we report 454 next-generation sequencing of the A. ipsilon pheromone gland transcriptome, identification and expression profiling of genes putatively involved in pheromone production, transport and degradation. A total of 23473 unigenes were obtained from the transcriptome analysis, 86% of which were A. ipsilon specific. 42 transcripts encoded enzymes putatively involved in pheromone biosynthesis, of which 15 were specifically, or mainly, expressed in the pheromone glands at 5 to 120-fold higher levels than in the body. Two transcripts encoding for a fatty acid synthase and a desaturase were highly abundant in the transcriptome and expressed more than 40-fold higher in the glands than in the body. The transcripts encoding for 2 acetyl-CoA carboxylases, 1 fatty acid synthase, 2 desaturases, 3 acyl-CoA reductases, 2 alcohol oxidases, 2 aldehyde reductases and 3 acetyltransferases were expressed at a significantly higher level in the pheromone glands than in the body. 17 esterase transcripts were not gland-specific and 7 of these were expressed highly in the antennae. Seven transcripts encoding odorant binding proteins (OBPs) and 8 encoding chemosensory proteins (CSPs) were identified. Two CSP transcripts (AipsCSP2, AipsCSP8) were highly abundant in the pheromone gland transcriptome and this was confirmed by qRT-PCR. One OBP (AipsOBP6) were pheromone gland-enriched and three OBPs (AipsOBP1, AipsOBP2 and AipsOBP4) were antennal-enriched. Based on these studies we proposed possible A. ipsilon biosynthesis pathways for major and minor sex pheromone components. Conclusions Our study identified genes potentially involved in sex pheromone biosynthesis and transport in A. ipsilon. The identified genes are likely to play essential roles in sex pheromone production, transport and degradation and could serve as targets to interfere with pheromone release. The identification of highly expressed CSPs and OBPs in the pheromone gland suggests that they may play a role in the binding, transport and release of sex pheromones during sex pheromone production in A. ipsilon and other Lepidoptera insects.
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88
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Pickett JA. Food security: intensification of agriculture is essential, for which current tools must be defended and new sustainable technologies invented. Food Energy Secur 2013. [DOI: 10.1002/fes3.32] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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89
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Babikova Z, Johnson D, Bruce T, Pickett JA, Gilbert L. How rapid is aphid-induced signal transfer between plants via common mycelial networks? Commun Integr Biol 2013; 6:e25904. [PMID: 24563703 PMCID: PMC3917958 DOI: 10.4161/cib.25904] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/25/2013] [Accepted: 07/25/2013] [Indexed: 11/23/2022] Open
Abstract
Arbuscular mycorrhizal (AM) fungi are important plant mutualists that can connect roots of neighboring plants to form common mycelial networks. A recent study demonstrated that these networks can act as conduits for aphid-induced signals between plants, activating chemical defenses in uninfested neighboring plants so that they become unattractive to aphids but attractive to their enemies (parasitoids). The benefit to the neighboring plants will increase if the signal speed is rapid, enabling them to respond before aphids attack. Here, we determine the speed of aphid-induced signal transfer between plants infested with aphids (“donor”) and neighboring aphid-free plants that were either connected or unconnected to the donor via a common mycelial network. Induced changes in plant volatiles from neighbors connected to donors started within 24 h of aphid infestation of donors. This demonstrates a rapid signal, implying potential benefit to plants receiving the signal, and raises intriguing ecological and evolutionary questions.
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Oluwafemi S, Dewhirst SY, Veyrat N, Powers S, Bruce TJA, Caulfield JC, Pickett JA, Birkett MA. Priming of Production in Maize of Volatile Organic Defence Compounds by the Natural Plant Activator cis-Jasmone. PLoS One 2013; 8:e62299. [PMID: 23840295 PMCID: PMC3694093 DOI: 10.1371/journal.pone.0062299] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 03/22/2013] [Indexed: 01/05/2023] Open
Abstract
cis-Jasmone (CJ) is a natural plant product that activates defence against herbivores in model and crop plants. In this study, we investigated whether CJ could prime defence in maize, Zea mays, against the leafhopper, Cicadulina storeyi, responsible for the transmission of maize streak virus (MSV). Priming occurs when a pre-treatment, in this case CJ, increases the potency and speed of a defence response upon subsequent attack on the plant. Here, we tested insect responses to plant volatile organic compounds (VOCs) using a Y-tube olfactometer bioassay. Our initial experiments showed that, in this system, there was no significant response of the herbivore to CJ itself and no difference in response to VOCs collected from unexposed plants compared to CJ exposed plants, both without insects. VOCs were then collected from C. storeyi-infested maize seedlings with and without CJ pre-treatment. The bioassay revealed a significant preference by this pest for VOCs from infested seedlings without the CJ pre-treatment. A timed series of VOC collections and bioassays showed that the effect was strongest in the first 22 h of insect infestation, i.e. before the insects had themselves induced a change in VOC emission. Chemical analysis showed that treatment of maize seedlings with CJ, followed by exposure to C. storeyi, led to a significant increase in emission of the defensive sesquiterpenes (E)-(1R,9S)-caryophyllene, (E)-α-bergamotene, (E)-β-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene, known to act as herbivore repellents. The chemical analysis explains the behavioural effects observed in the olfactometer, as the CJ treatment caused plants to emit a blend of VOCs comprising more of the repellent components in the first 22 h of insect infestation than control plants. The speed and potency of VOC emission was increased by the CJ pre-treatment. This is the first indication that CJ can prime plants for enhanced production of defensive VOCs antagonist towards herbivores.
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Babikova Z, Gilbert L, Bruce TJA, Birkett M, Caulfield JC, Woodcock C, Pickett JA, Johnson D. Underground signals carried through common mycelial networks warn neighbouring plants of aphid attack. Ecol Lett 2013; 16:835-43. [DOI: 10.1111/ele.12115] [Citation(s) in RCA: 244] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/04/2012] [Accepted: 03/25/2013] [Indexed: 11/30/2022]
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92
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93
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94
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Hamilton ML, Kuate SP, Brazier-Hicks M, Caulfield JC, Rose R, Edwards R, Torto B, Pickett JA, Hooper AM. Elucidation of the biosynthesis of the di-C-glycosylflavone isoschaftoside, an allelopathic component from Desmodium spp. that inhibits Striga spp. development. PHYTOCHEMISTRY 2012; 84:169-76. [PMID: 22959223 DOI: 10.1016/j.phytochem.2012.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/06/2012] [Accepted: 08/11/2012] [Indexed: 06/01/2023]
Abstract
Isoschaftoside, an allelopathic di-C-glycosylflavone from Desmodium spp. root exudates, is biosynthesised through sequential glucosylation and arabinosylation of 2-hydroxynaringenin with UDP-glucose and UDP-arabinose. Complete conversion to the flavone requires chemical dehydration implying a dehydratase enzyme has a role in vivo to complete the biosynthesis. The C-glucosyltransferase has been partially characterised and its activity demonstrated in highly purified fractions.
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Magalhães DM, Borges M, Laumann RA, Sujii ER, Mayon P, Caulfield JC, Midega CAO, Khan ZR, Pickett JA, Birkett MA, Blassioli-Moraes MC. Semiochemicals from herbivory induced cotton plants enhance the foraging behavior of the cotton boll weevil, Anthonomus grandis. J Chem Ecol 2012. [PMID: 23179097 DOI: 10.1007/s10886-012-0216-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The boll weevil, Anthonomus grandis, has been monitored through deployment of traps baited with aggregation pheromone components. However, field studies have shown that the number of insects caught in these traps is significantly reduced during cotton squaring, suggesting that volatiles produced by plants at this phenological stage may be involved in attraction. Here, we evaluated the chemical profile of volatile organic compounds (VOCs) emitted by undamaged or damaged cotton plants at different phenological stages, under different infestation conditions, and determined the attractiveness of these VOCs to adults of A. grandis. In addition, we investigated whether or not VOCs released by cotton plants enhanced the attractiveness of the aggregation pheromone emitted by male boll weevils. Behavioral responses of A. grandis to VOCs from conspecific-damaged, heterospecific-damaged (Spodoptera frugiperda and Euschistus heros) and undamaged cotton plants, at different phenological stages, were assessed in Y-tube olfactometers. The results showed that volatiles emitted from reproductive cotton plants damaged by conspecifics were attractive to adults boll weevils, whereas volatiles induced by heterospecific herbivores were not as attractive. Additionally, addition of boll weevil-induced volatiles from reproductive cotton plants to aggregation pheromone gave increased attraction, relative to the pheromone alone. The VOC profiles of undamaged and mechanically damaged cotton plants, in both phenological stages, were not different. Chemical analysis showed that cotton plants produced qualitatively similar volatile profiles regardless of damage type, but the quantities produced differed according to the plant's phenological stage and the herbivore species. Notably, vegetative cotton plants released higher amounts of VOCs compared to reproductive plants. At both stages, the highest rate of VOC release was observed in A. grandis-damaged plants. Results show that A. grandis uses conspecific herbivore-induced volatiles in host location, and that homoterpene compounds, such as (E)-4,8-dimethylnona-1,3,7-triene and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene and the monoterpene (E)-ocimene, may be involved in preference for host plants at the reproductive stage.
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Ukeh DA, Woodcock CM, Pickett JA, Birkett MA. Identification of Host Kairomones from Maize, Zea mays, for the Maize Weevil, Sitophilus zeamais. J Chem Ecol 2012; 38:1402-9. [DOI: 10.1007/s10886-012-0191-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 09/14/2012] [Accepted: 09/21/2012] [Indexed: 10/27/2022]
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97
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Dewhirst SY, Birkett MA, Loza-Reyes E, Martin JL, Pye BJ, Smart LE, Hardie J, Pickett JA. Activation of defence in sweet pepper, Capsicum annum, by cis-jasmone, and its impact on aphid and aphid parasitoid behaviour. PEST MANAGEMENT SCIENCE 2012; 68:1419-29. [PMID: 22696464 DOI: 10.1002/ps.3326] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 02/22/2012] [Accepted: 03/28/2012] [Indexed: 05/24/2023]
Abstract
BACKGROUND Two important pests of the sweet pepper, Capsicum annuum, are the peach potato aphid, Myzus persicae, and the glasshouse potato aphid, Aulacorthum solani. Current aphid control measures include the use of biological control agents, i.e., parasitic wasps, but with varying levels of success. One option to increase parasitoid efficiency is to activate plant defence. Therefore, sweet pepper plants were treated with the naturally occurring plant defence activator cis-jasmone, and its impact upon the behaviour and development of aphids and aphid parasitoids was investigated. RESULTS Growth rate studies revealed that the intrinsic rate of population increase of A. solani and M. persicae on sweet pepper plants treated with cis-jasmone (cJSP) was not affected compared with untreated plants (UnSP), but the positive behavioural response of alate M. persicae towards the volatile organic compounds (VOCs) from UnSP was eliminated by cis-jasmone treatment 48 h previously (cJSP48). In addition, the aphid parasitoid Aphidius ervi preferred VOCs from cJSP48 compared with UnSP, and a significant increase in foraging time was also observed on cJSP. Analysis of VOCs collected from cJSP48 revealed differences compared with UnSP. CONCLUSION There is evidence that treatment with cis-jasmone has the potential to improve protection of sweet pepper against insect pests.
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Xu P, Hooper AM, Pickett JA, Leal WS. Specificity determinants of the silkworm moth sex pheromone. PLoS One 2012; 7:e44190. [PMID: 22957053 PMCID: PMC3434217 DOI: 10.1371/journal.pone.0044190] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022] Open
Abstract
The insect olfactory system, particularly the peripheral sensory system for sex pheromone reception in male moths, is highly selective, but specificity determinants at the receptor level are hitherto unknown. Using the Xenopus oocyte recording system, we conducted a thorough structure-activity relationship study with the sex pheromone receptor of the silkworm moth, Bombyx mori, BmorOR1. When co-expressed with the obligatory odorant receptor co-receptor (BmorOrco), BmorOR1 responded in a dose-dependent fashion to both bombykol and its related aldehyde, bombykal, but the threshold of the latter was about one order of magnitude higher. Solubilizing these ligands with a pheromone-binding protein (BmorPBP1) did not enhance selectivity. By contrast, both ligands were trapped by BmorPBP1 leading to dramatically reduced responses. The silkworm moth pheromone receptor was highly selective towards the stereochemistry of the conjugated diene, with robust response to the natural (10E,12Z)-isomer and very little or no response to the other three isomers. Shifting the conjugated diene towards the functional group or elongating the carbon chain rendered these molecules completely inactive. In contrast, an analogue shortened by two omega carbons elicited the same or slightly higher responses than bombykol. Flexibility of the saturated C1–C9 moiety is important for function as addition of a double or triple bond in position 4 led to reduced responses. The ligand is hypothesized to be accommodated by a large hydrophobic cavity within the helical bundle of transmembrane domains.
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Chamberlain K, Briens M, Jacobs JH, Clark SJ, Pickett JA. Use of honey bees (Apis mellifera L.) to detect the presence of Mediterranean fruit fly (Ceratitis capitata Wiedemann) larvae in Valencia oranges. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2012; 92:2050-2054. [PMID: 22653619 DOI: 10.1002/jsfa.5742] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 04/04/2012] [Accepted: 04/21/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND When fruit deteriorates a characteristic profile of volatile chemicals is produced that is different from that produced by healthy fruits. The identification of such chemicals allows the possibility of monitoring the fruit for early signs of deterioration with biological sensors. The use of honey bees and other insects as biological sensors is well known. This study aimed to identify the volatiles produced by oranges infested with larvae of the Mediterranean fruit fly and to test the ability of honey bees, conditioned to this volatile chemical profile, to detect such oranges. RESULTS Seventeen compounds that were present in higher concentrations in the volatile profiles of infested oranges than in those of insect-free fruits were mixed at the same relative concentrations as those in the collected volatiles of infested oranges. The synthetic mixture was used to train honey bees by classical Pavlovian conditioning and subsequent tests showed that they were then able to discriminate between medfly-infested and uninfested oranges. CONCLUSION This study demonstrates an innovative way of detecting, at an early stage, the symptoms of damage to oranges by the Mediterranean fruit fly.
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Dufour S, Castets P, Pickett JA, Hooper AM. A diastereoselective synthesis of (1SR,3SR,7RS)-3-methyl-α-himachalene, the sex pheromone of the sandfly, Lutzomyia longipalpis (Diptera: Psychodidae). Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.04.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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