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Scarano F, Deivarajan Suresh M, Tiraboschi E, Cabirol A, Nouvian M, Nowotny T, Haase A. Geosmin suppresses defensive behaviour and elicits unusual neural responses in honey bees. Sci Rep 2023; 13:3851. [PMID: 36890201 PMCID: PMC9995521 DOI: 10.1038/s41598-023-30796-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 03/01/2023] [Indexed: 03/10/2023] Open
Abstract
Geosmin is an odorant produced by bacteria in moist soil. It has been found to be extraordinarily relevant to some insects, but the reasons for this are not yet fully understood. Here we report the first tests of the effect of geosmin on honey bees. A stinging assay showed that the defensive behaviour elicited by the bee's alarm pheromone component isoamyl acetate (IAA) is strongly suppressed by geosmin. Surprisingly, the suppression is, however, only present at very low geosmin concentrations, and disappears at higher concentrations. We investigated the underlying mechanisms at the level of the olfactory receptor neurons by means of electroantennography, finding the responses to mixtures of geosmin and IAA to be lower than to pure IAA, suggesting an interaction of both compounds at the olfactory receptor level. Calcium imaging of the antennal lobe (AL) revealed that neuronal responses to geosmin decreased with increasing concentration, correlating well with the observed behaviour. Computational modelling of odour transduction and coding in the AL suggests that a broader activation of olfactory receptor types by geosmin in combination with lateral inhibition could lead to the observed non-monotonic increasing-decreasing responses to geosmin and thus underlie the specificity of the behavioural response to low geosmin concentrations.
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Affiliation(s)
- Florencia Scarano
- Department of Physics, University of Trento, 38120, Trento, Italy.,Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068, Rovereto, Italy
| | | | - Ettore Tiraboschi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068, Rovereto, Italy
| | - Amélie Cabirol
- Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068, Rovereto, Italy.,Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Morgane Nouvian
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany.,Zukunftskolleg, University of Konstanz, 78464, Konstanz, Germany
| | - Thomas Nowotny
- School of Engineering and Informatics, University of Sussex, Brighton, BN1 9QJ, UK.
| | - Albrecht Haase
- Department of Physics, University of Trento, 38120, Trento, Italy. .,Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068, Rovereto, Italy.
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A flavin-dependent monooxygenase produces nitrogenous tomato aroma volatiles using cysteine as a nitrogen source. Proc Natl Acad Sci U S A 2022; 119:2118676119. [PMID: 35131946 PMCID: PMC8851548 DOI: 10.1073/pnas.2118676119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2021] [Indexed: 11/19/2022] Open
Abstract
Aroma is an important factor in consumer perception and acceptance of fresh tomatoes and involves a cocktail of several dozen compounds. Tomato fruits produce uncommon nitrogen-containing volatiles derived mainly from the amino acids leucine and phenylalanine. These volatiles have strong positive correlations with consumer liking. We show that an enzyme active in ripening tomatoes is responsible for the production of all nitrogenous volatiles in tomato fruit, at the expense of substrates derived from cysteine and volatile aldehydes. This discovery defines a cysteine-dependent route to nitrogenous volatiles in plants, prompting a reconsideration of the impact of sulfur metabolism on tomato flavor and quality. Tomato (Solanum lycopersicum) produces a wide range of volatile chemicals during fruit ripening, generating a distinct aroma and contributing to the overall flavor. Among these volatiles are several aromatic and aliphatic nitrogen-containing compounds for which the biosynthetic pathways are not known. While nitrogenous volatiles are abundant in tomato fruit, their content in fruits of the closely related species of the tomato clade is highly variable. For example, the green-fruited species Solanum pennellii are nearly devoid, while the red-fruited species S. lycopersicum and Solanum pimpinellifolium accumulate high amounts. Using an introgression population derived from S. pennellii, we identified a locus essential for the production of all the detectable nitrogenous volatiles in tomato fruit. Silencing of the underlying gene (SlTNH1;Solyc12g013690) in transgenic plants abolished production of aliphatic and aromatic nitrogenous volatiles in ripe fruit, and metabolomic analysis of these fruit revealed the accumulation of 2-isobutyl-tetrahydrothiazolidine-4-carboxylic acid, a known conjugate of cysteine and 3-methylbutanal. Biosynthetic incorporation of stable isotope-labeled precursors into 2-isobutylthiazole and 2-phenylacetonitrile confirmed that cysteine provides the nitrogen atom for all nitrogenous volatiles in tomato fruit. Nicotiana benthamiana plants expressing SlTNH1 readily transformed synthetic 2-substituted tetrahydrothiazolidine-4-carboxylic acid substrates into a mixture of the corresponding 2-substituted oxime, nitro, and nitrile volatiles. Distinct from other known flavin-dependent monooxygenase enzymes in plants, this tetrahydrothiazolidine-4-carboxylic acid N-hydroxylase catalyzes sequential hydroxylations. Elucidation of this pathway is a major step forward in understanding and ultimately improving tomato flavor quality.
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Abstract
A concise stereoselective approach to functionalized δ-lactone skeleton from monosilylated ethylene glycol as a starting material and its application to the asymmetric total synthesis of (−)-trans-aerangis lactone have been demonstrated. The synthesis utilizes the organocatalyzed MacMillan’s cross aldol reaction as a key step.
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Affiliation(s)
- Rachana Pandey
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala 147 001, India
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala 147 001, India
| | - Ranjana Prakash
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala 147 001, India
- School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala 147 001, India
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Sørensen M, Neilson EHJ, Møller BL. Oximes: Unrecognized Chameleons in General and Specialized Plant Metabolism. MOLECULAR PLANT 2018; 11:95-117. [PMID: 29275165 DOI: 10.1016/j.molp.2017.12.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 05/19/2023]
Abstract
Oximes (R1R2C=NOH) are nitrogen-containing chemical constituents that are formed in species representing all kingdoms of life. In plants, oximes are positioned at important metabolic bifurcation points between general and specialized metabolism. The majority of plant oximes are amino acid-derived metabolites formed by the action of a cytochrome P450 from the CYP79 family. Auxin, cyanogenic glucosides, glucosinolates, and a number of other bioactive specialized metabolites including volatiles are produced from oximes. Oximes with the E configuration have high biological activity compared with Z-oximes. Oximes or their derivatives have been demonstrated or proposed to play roles in growth regulation, plant defense, pollinator attraction, and plant communication with the surrounding environment. In addition, oxime-derived products may serve as quenchers of reactive oxygen species and storage compounds for reduced nitrogen that may be released on demand by the activation of endogenous turnover pathways. As highly bioactive molecules, chemically synthesized oximes have found versatile uses in many sectors of society, especially in the agro- and medical sectors. This review provides an update on the structural diversity, occurrence, and biosynthesis of oximes in plants and discusses their role as key players in plant general and specialized metabolism.
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Affiliation(s)
- Mette Sørensen
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark; VILLUM Center for Plant Plasticity, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark
| | - Elizabeth H J Neilson
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark; VILLUM Center for Plant Plasticity, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark
| | - Birger Lindberg Møller
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark; VILLUM Center for Plant Plasticity, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark; Center for Synthetic Biology, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Copenhagen, Denmark.
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Kantsa A, Sotiropoulou S, Vaitis M, Petanidou T. Plant Volatilome in Greece: a Review on the Properties, Prospects, and Chemogeography. Chem Biodivers 2016; 12:1466-80. [PMID: 26460555 DOI: 10.1002/cbdv.201500171] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Indexed: 11/08/2022]
Abstract
Knowing plant volatile chemodiversity and its distribution is essential in order to study biological processes, to estimate the plants' value in use, and to establish sustainable exploitation practices. Yet, attempts to collect and assess data on scent diversity and properties in well-defined geographical areas are rare. Here, we developed a geo-referenced database of the plant volatilome in Greece by consolidating the results included in 116 research articles published in the last 25 years. The data set compiled includes 999 volatile organic compounds distributed into 178 plant taxa, 59 genera, and 19 families. Distillation is the acquisition method almost exclusively used, whereas headspace techniques that would allow the study of subtle ecological processes are generally lacking. Sesquiterpenes show the greatest richness of compounds, followed by monoterpenes and aliphatics. We assess the volatility of the compounds using the normal boiling point (nBP) as its reverse indicator, and we present the volatility spectra of the blends of the genera studied. Mean nBPs vary among genera, with maximal differences as wide as 118.4°. Finally, we feature basic chemodiversity maps for three aromatic plants, and discuss their importance and prospects as a special case of natural resources maps.
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Affiliation(s)
- Aphrodite Kantsa
- Laboratory of Biogeography & Ecology, Department of Geography, University of the Aegean, GR-81100, Mytilene, (phone: +30-22510-36423; fax: +30-22510-36423).
| | - Stavroula Sotiropoulou
- Laboratory of Biogeography & Ecology, Department of Geography, University of the Aegean, GR-81100, Mytilene, (phone: +30-22510-36423; fax: +30-22510-36423)
| | - Michail Vaitis
- Laboratory of Cartography & Geoinformatics, Department of Geography, University of the Aegean, GR-81100, Mytilene
| | - Theodora Petanidou
- Laboratory of Biogeography & Ecology, Department of Geography, University of the Aegean, GR-81100, Mytilene, (phone: +30-22510-36423; fax: +30-22510-36423)
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Suinyuy TN, Donaldson JS, Johnson SD. Geographical matching of volatile signals and pollinator olfactory responses in a cycad brood-site mutualism. Proc Biol Sci 2016; 282:20152053. [PMID: 26446814 DOI: 10.1098/rspb.2015.2053] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Brood-site mutualisms represent extreme levels of reciprocal specialization between plants and insect pollinators, raising questions about whether these mutualisms are mediated by volatile signals and whether these signals and insect responses to them covary geographically in a manner expected from coevolution. Cycads are an ancient plant lineage in which almost all extant species are pollinated through brood-site mutualisms with insects. We investigated whether volatile emissions and insect olfactory responses are matched across the distribution range of the African cycad Encephalartos villosus. This cycad species is pollinated by the same beetle species across its distribution, but cone volatile emissions are dominated by alkenes in northern populations, and by monoterpenes and a pyrazine compound in southern populations. In reciprocal choice experiments, insects chose the scent of cones from the local region over that of cones from the other region. Antennae of beetles from northern populations responded mainly to alkenes, while those of beetles from southern populations responded mainly to pyrazine. In bioassay experiments, beetles were most strongly attracted to alkenes in northern populations and to the pyrazine compound in southern populations. Geographical matching of cone volatiles and pollinator olfactory preference is consistent with coevolution in this specialized mutualism.
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Affiliation(s)
- Terence N Suinyuy
- School of Life Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg 3201, South Africa Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag X7, Claremont, Cape Town 7735, South Africa Department of Biological Sciences, University of Cape Town, P/Bag Rondebosch, Cape Town 7701, South Africa
| | - John S Donaldson
- Kirstenbosch Research Centre, South African National Biodiversity Institute, P/Bag X7, Claremont, Cape Town 7735, South Africa Department of Biological Sciences, University of Cape Town, P/Bag Rondebosch, Cape Town 7701, South Africa Research Associate, Fairchild Tropical Botanic Garden, 10901 Old Cutler Road, Coral Gables, Miami, FL 33156, USA
| | - Steven D Johnson
- School of Life Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg 3201, South Africa
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Nielsen LJ, Møller BL. Scent emission profiles from Darwin's orchid--Angraecum sesquipedale: Investigation of the aldoxime metabolism using clustering analysis. PHYTOCHEMISTRY 2015; 120:3-18. [PMID: 26603277 DOI: 10.1016/j.phytochem.2015.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 10/12/2015] [Accepted: 10/16/2015] [Indexed: 06/05/2023]
Abstract
The display of scent is crucial for plants in attracting pollinating insects to flowers and ensuring successful pollination and reproduction. The large number of aldoxime volatile species present in the scent of the Madagascan orchid Angraecum sesquipedale has been suggested to play a primary role in attracting the sphingid moth Xanthopan morgani praedicta. By solid phase micro-extraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS), we monitored the scent release from different flowers of a single orchid, day and night throughout the entire flowering period. In separate experiments, the diurnal release was monitored in 3h intervals and the tissue specific release from the different floral parts was tracked. Numerous novel compounds related to the aldoxime metabolism not previously detected in A. sesquipedale were identified and positioned into a proposed pathway for aldoxime metabolism. From the results, we hypothesize that (E/Z)-phenylacetaldoxime and its derivatives could be important attractants for the pollinating moth X. morgani praedicta. By applying an untargeted Partitioning Around Medoids (PAM) cluster analysis to the metabolite profiles in the scent, the proposed pathways for the formation of aldoximes were substantiated. With this study, we demonstrate the powerful utility of a bioinformatics tool to aid in the elucidation of the routes of formation for volatiles and provide a benchmark and guidelines for future detailed observations of hawkmoth pollination of Angraecum species, and in particular A. sesquipedale, in the wild.
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Affiliation(s)
- Lasse Janniche Nielsen
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Copenhagen, Frederiksberg, Denmark; VILLUM Research Center of Excellence "Plant Plasticity", University of Copenhagen, Thorvaldsensvej 40, DK-1871 Copenhagen, Frederiksberg, Denmark
| | - Birger Lindberg Møller
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Copenhagen, Frederiksberg, Denmark; VILLUM Research Center of Excellence "Plant Plasticity", University of Copenhagen, Thorvaldsensvej 40, DK-1871 Copenhagen, Frederiksberg, Denmark.
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Kürkcüoglu M, Baser KHC. Headspace Volatiles of Three Turkish Plants. JOURNAL OF ESSENTIAL OIL RESEARCH 2010. [DOI: 10.1080/10412905.2010.9700353] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Azuma H, Nagasawa JI, Setoguchi H. Floral scent emissions from Asarum yaeyamense and related species. BIOCHEM SYST ECOL 2010. [DOI: 10.1016/j.bse.2010.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Habel A, Boland W. Efficient and flexible synthesis of chiral γ- and δ-lactones. Org Biomol Chem 2008; 6:1601-4. [DOI: 10.1039/b801514g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Some flowering plants mimic the scent and appearance of mushroom fruiting bodies. Fungi may also mimic flowers. In addition, infection of plants by certain fungi can direct the plant to develop nonfunctional floral-like structures that nonetheless primarily serve the reproductive advantage of the fungus. These various mimicries may serve to attract insects that in turn spread fungal spores or plant pollen, thus facilitating sexual reproduction of the cryptic organism.
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Affiliation(s)
- Roman Kaiser
- Givaudan Schweiz AG, Fragrance Research, Ueberlandstrasse 138, CH-8600 Dubendorf, Switzerland.
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Kraft P, Swift KAD. Editorial. Chem Biodivers 2004. [DOI: 10.1002/cbdv.200490141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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