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  • 1
    Language: English
    In: Plant, cell and environment, 2014-08, Vol.37 (8), p.1909-1923
    Description: After herbivory, plants release volatile organic compounds from damaged foliage as well as from nearby undamaged leaves that attract herbivore enemies. Little is known about what controls the volatile emission differences between damaged and undamaged tissues and how these affect the orientation of herbivore enemies. We investigated volatile emission from damaged and adjacent undamaged foliage of black poplar (Populus nigra) after herbivory by gypsy moth (Lymantria dispar) caterpillars and determined the compounds mediating the attraction of the gypsy moth parasitoid Glyptapanteles liparidis (Braconidae). Female parasitoids were more attracted to gypsy moth‐damaged leaves than to adjacent non‐damaged leaves. The most characteristic volatiles of damaged versus neighbouring undamaged leaves included terpenes, green leaf volatiles and nitrogen‐containing compounds, such as aldoximes and nitriles. Electrophysiological recordings and olfactometer bioassays demonstrated the importance of nitrogenous volatiles. Under field conditions, parasitic Hymenoptera were more attracted to traps baited with these substances than most other compounds. The differences in volatile emission profiles between damaged and undamaged foliage appear to be regulated by jasmonate signalling and the local activation of volatile biosynthesis. We conclude that characteristic volatiles from damaged black poplar foliage are essential cues enabling parasitoids to find their hosts. Our study aimed to understand the phenomenon of volatile‐mediated natural enemy recruitment in a deciduous tree species native to Europe, black poplar (Populus nigra). Our results show that minor nitrogenous compounds characterize the herbivore induced black poplar volatile blend and are only emitted locally at the herbivore damaged sites. Female Glyptapanteles liparidis parasitoids are attracted to odors released from local herbivore damaged black poplar leaves. Electrophysiological recordings and behavioral essays with individual compounds, both under laboratory and field conditions, suggest that minor nitrogenous compounds, rather than highly abundant terpenoids and green leaf volatiles, are key substances mediating the recruitment of parasitic Hymenopterans in poplar trees.
    Subject(s): Lymantria dispar; phytohormones ; Populus nigra ; herbivore‐induced volatiles ; indirect defence ; cytochrome P450 ; Braconidae ; Glyptapanteles liparidis ; terpene synthase ; Salicaceae ; Fundamental and applied biological sciences. Psychology ; Biological and medical sciences ; Plant Leaves - chemistry ; Genes, Plant ; Moths - parasitology ; Populus - chemistry ; Genotype ; Herbivory ; Populus - genetics ; Populus - physiology ; Terpenes - chemistry ; Animals ; Larva ; Moths - physiology ; Pheromones - chemistry ; Female ; Wasps - physiology ; Volatile Organic Compounds - chemistry ; Plant Leaves - physiology ; Volatile organic compounds ; Biological products ; Gypsy moth ; Analysis ; Physiological aspects ; Nitriles ; Wasps ; Terpenes ; Moths ; Plant hormones
    ISSN: 0140-7791
    E-ISSN: 1365-3040
    Source: Alma/SFX Local Collection
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  • 2
    Language: English
    In: BMC plant biology, 2012-06-08, Vol.12 (1), p.84-84
    Description: The essential oil of chamomile, one of the oldest and agronomically most important medicinal plant species in Europe, has significant antiphlogistic, spasmolytic and antimicrobial activities. It is rich in chamazulene, a pharmaceutically active compound spontaneously formed during steam distillation from the sesquiterpene lactone matricine. Chamomile oil also contains sesquiterpene alcohols and hydrocarbons which are produced by the action of terpene synthases (TPS), the key enzymes in constructing terpene carbon skeletons. Here, we present the identification and characterization of five TPS enzymes contributing to terpene biosynthesis in chamomile (Matricaria recutita). Four of these enzymes were exclusively expressed in above-ground organs and produced the common terpene hydrocarbons (-)-(E)-β-caryophyllene (MrTPS1), (+)-germacrene A (MrTPS3), (E)-β-ocimene (MrTPS4) and (-)-germacrene D (MrTPS5). A fifth TPS, the multiproduct enzyme MrTPS2, was mainly expressed in roots and formed several Asteraceae-specific tricyclic sesquiterpenes with (-)-α-isocomene being the major product. The TPS transcript accumulation patterns in different organs of chamomile were consistent with the abundance of the corresponding TPS products isolated from these organs suggesting that the spatial regulation of TPS gene expression qualitatively contribute to terpene composition. The terpene synthases characterized in this study are involved in the organ-specific formation of essential oils in chamomile. While the products of MrTPS1, MrTPS2, MrTPS4 and MrTPS5 accumulate in the oils without further chemical alterations, (+)-germacrene A produced by MrTPS3 accumulates only in trace amounts, indicating that it is converted into another compound like matricine. Thus, MrTPS3, but also the other TPS genes, are good markers for further breeding of chamomile cultivars rich in pharmaceutically active essential oils.
    Subject(s): Alkyl and Aryl Transferases - metabolism ; Molecular Sequence Data ; Plant Roots - genetics ; Plant Components, Aerial - enzymology ; Phylogeny ; Terpenes - chemistry ; Terpenes - metabolism ; Alkyl and Aryl Transferases - genetics ; Chamomile - chemistry ; Cloning, Molecular ; Oils, Volatile - metabolism ; Plant Proteins - metabolism ; Lactones - chemistry ; Amino Acid Sequence ; Chamomile - enzymology ; Plant Components, Aerial - chemistry ; Gene Expression Regulation, Plant - genetics ; Lactones - metabolism ; Organ Specificity ; Plant Components, Aerial - genetics ; Plant Proteins - genetics ; Sequence Alignment ; Plant Roots - chemistry ; Plant Oils - metabolism ; Plant Roots - enzymology ; Chamomile - genetics ; Medicinal plants ; Enzymes ; Sesquiterpenes ; Medicine, Botanic ; Genes ; Genetic research ; Physiological aspects ; Medicine, Herbal ; Gene expression ; Chamomile ; Essences and essential oils
    ISSN: 1471-2229
    E-ISSN: 1471-2229
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 3
    Language: English
    In: The Plant cell, 2016-10-01, Vol.28 (10), p.2651-2665
    Description: Plant volatiles not only have multiple defense functions against herbivores, fungi, and bacteria, but also have been implicated in signaling within the plant and toward other organisms. Elucidating the function of individual plant volatiles will require more knowledge of their biosynthesis and regulation in response to external stimuli. By exploiting the variation of herbivore-induced volatiles among 26 maize ( ) inbred lines, we conducted a nested association mapping and genome-wide association study (GWAS) to identify a set of quantitative trait loci (QTLs) for investigating the pathways of volatile terpene production. The most significant identified QTL affects the emission of ( )-nerolidol, linalool, and the two homoterpenes ( )-3,8-dimethyl-1,4,7-nonatriene (DMNT) and ( )-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). GWAS associated a single nucleotide polymorphism in the promoter of the gene encoding the terpene synthase TPS2 with this QTL. Biochemical characterization of TPS2 verified that this plastid-localized enzyme forms linalool, ( )-nerolidol, and ( )-geranyllinalool. The subsequent conversion of ( )-nerolidol into DMNT maps to a P450 monooxygenase, CYP92C5, which is capable of converting nerolidol into DMNT by oxidative degradation. A QTL influencing TMTT accumulation corresponds to a similar monooxygenase, CYP92C6, which is specific for the conversion of ( )-geranyllinalool to TMTT. The DMNT biosynthetic pathway and both monooxygenases are distinct from those previously characterized for DMNT and TMTT synthesis in , suggesting independent evolution of these enzymatic activities.
    Subject(s): RESEARCH ARTICLES ; Arabidopsis - genetics ; Arabidopsis Proteins - metabolism ; Genome-Wide Association Study ; Sesquiterpenes - metabolism ; Monoterpenes - metabolism ; Arabidopsis - metabolism ; Quantitative Trait Loci - genetics
    ISSN: 1040-4651
    E-ISSN: 1532-298X
    Source: American Society of Plant Biologists
    Source: JSTOR Life Sciences
    Source: JSTOR Ecology & Botany II
    Source: Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals
    Source: PubMed Central
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  • 4
    Language: English
    In: BMC plant biology, 2014-10-11, Vol.14 (1), p.270-270
    Description: As a response to caterpillar feeding, poplar releases a complex mixture of volatiles which comprises several classes of compounds. Poplar volatiles have been reported to function as signals in plant-insect interactions and intra- and inter-plant communication. Although the volatile blend is dominated by mono- and sesquiterpenes, there is much to be learned about their formation in poplar. Here we report the terpene synthase (TPS) gene family of western balsam poplar (Populus trichocarpa) consisting of 38 members. Eleven TPS genes (PtTPS5-15) could be isolated from gypsy moth (Lymantria dispar)-damaged P. trichocarpa leaves and heterologous expression in Escherichia coli revealed TPS activity for ten of the encoded enzymes. Analysis of TPS transcript abundance in herbivore-damaged leaves and undamaged control leaves showed that seven of the genes, PtTPS6, PtTPS7, PtTPS9, PtTPS10, PtTPS12, PtTPS13 and PtTPS15, were significantly upregulated after herbivory. Gypsy moth-feeding on individual leaves of P. trichocarpa trees resulted in induced volatile emission from damaged leaves, but not from undamaged adjacent leaves. Moreover, the concentration of jasmonic acid and its isoleucine conjugates as well as PtTPS6 gene expression were exclusively increased in the damaged leaves, suggesting that no systemic induction occurred within the tree. Our data indicate that the formation of herbivore-induced volatile terpenes in P. trichocarpa is mainly regulated by transcript accumulation of multiple TPS genes and is likely mediated by jasmonates. The specific local emission of volatiles from herbivore-damaged leaves might help herbivore enemies to find their hosts or prey in the tree canopy.
    Subject(s): Plant Proteins - genetics ; Populus - enzymology ; Animals ; Terpenes - metabolism ; Plant Leaves - genetics ; Plant Leaves - metabolism ; Alkyl and Aryl Transferases - genetics ; Herbivory - physiology ; Alkyl and Aryl Transferases - metabolism ; Plant Proteins - metabolism ; Genes ; Analysis ; Escherichia coli ; Monoterpenes ; Populus trichocarpa ; Terpene synthase gene family ; Volatiles ; Sesquiterpenes ; Jasmonic acid
    ISSN: 1471-2229
    E-ISSN: 1471-2229
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 5
    Language: English
    In: The Plant cell, 2013-11-01, Vol.25 (11), p.4737-4754
    Description: Aldoximes are known as floral and vegetative plant volatiles but also as biosynthetic intermediates for other plant defense compounds. While the cytochrome P450 monooxygenases (CYP) from the CYP79 family forming aldoximes as biosynthetic intermediates have been intensively studied, little is known about the enzymology of volatile aldoxime formation. We characterized two P450 enzymes, CYP79D6v3 and CYP79D7v2, which are involved in herbivore-induced aldoxime formation in western balsam poplar (Populus trichocarpa). Heterologous expression in Saccharomyces cerevisiae revealed that both enzymes produce a mixture of different aldoximes. Knockdown lines of CYP79D6/7 in gray poplar (Populus × canescens) exhibited a decreased emission of aldoximes, nitriles, and alcohols, emphasizing that the CYP79s catalyze the first step in the formation of a complex volatile blend. Aldoxime emission was found to be restricted to herbivore-damaged leaves and is closely correlated with CYP79D6 and CYP79D7 gene expression. The semi-volatile phenylacetaldoxime decreased survival and weight gain of gypsy moth (Lymantria dispar) caterpillars, suggesting that aldoximes may be involved in direct defense. The wide distribution of volatile aldoximes throughout the plant kingdom and the presence of CYP79 genes in all sequenced genomes of angiosperms suggest that volatile formation mediated by CYP79s is a general phenomenon in the plant kingdom.
    Subject(s): Oximes ; Enzymes ; Leaves ; RESEARCH ARTICLES ; Caterpillars ; Amino acids ; Nitriles ; Biosynthesis ; Plants ; Herbivores ; Moths ; Volatile Organic Compounds - metabolism ; Cytochrome P-450 Enzyme System - metabolism ; Populus - genetics ; Alcohols - metabolism ; Gene Knockdown Techniques ; Oximes - metabolism ; Plants, Genetically Modified ; Populus - metabolism ; Gene Expression Regulation, Plant ; Moths - physiology ; Plant Proteins - metabolism ; Nitriles - metabolism ; Phenylalanine - metabolism ; Tobacco - metabolism ; Mortality ; Volatile Organic Compounds - analysis ; Herbivory ; Genome, Plant ; Populus - physiology ; Moths - growth & development ; Plant Proteins - genetics ; Animals ; Plant Leaves - genetics ; Plant Leaves - metabolism ; Tobacco - genetics ; Cytochrome P-450 Enzyme System - genetics ; Oximes - pharmacology ; Moths - drug effects ; Physiological aspects ; Poplar ; Botanical research ; Health aspects ; Cytochrome P-450 ; s
    ISSN: 1040-4651
    E-ISSN: 1532-298X
    Source: American Society of Plant Biologists
    Source: JSTOR Life Sciences
    Source: JSTOR Ecology & Botany II
    Source: Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals
    Source: PubMed Central
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  • 6
    Language: English
    In: Molecules (Basel, Switzerland), 2019-07-01, Vol.24 (13), p.2408
    Description: In response to insect herbivory, poplar releases a blend of volatiles that plays important roles in plant defense. Although the volatile bouquet is highly complex and comprises several classes of compounds, it is dominated by mono- and sesquiterpenes. The most common precursors for mono- and sesquiterpenes, geranyl diphosphate (GPP) and (E,E)-farnesyl diphosphate (FPP), respectively, are in general produced by homodimeric or heterodimeric trans-isopentenyl diphosphate synthases (trans-IDSs) that belong to the family of prenyltransferases. To understand the molecular basis of herbivory-induced terpene formation in poplar, we investigated the trans-IDS gene family in the western balsam poplar Populus trichocarpa. Sequence comparisons suggested that this species possesses a single FPP synthase gene (PtFPPS1) and four genes encoding two large subunits (PtGPPS1.LSU and PtGPPS2.LSU) and two small subunits (PtGPPS.SSU1 and PtGPPS.SSU2) of GPP synthases. Transcript accumulation of PtGPPS1.LSU and PtGPPS.SSU1 was significantly upregulated upon leaf herbivory, while the expression of PtFPPS1, PtGPPS2.LSU, and PtGPPS.SSU2 was not influenced by the herbivore treatment. Heterologous expression and biochemical characterization of recombinant PtFPPS1, PtGPPS1.LSU, and PtGPPS2.LSU confirmed their respective IDS activities. Recombinant PtGPPS.SSU1 and PtGPPS.SSU2, however, had no enzymatic activity on their own, but PtGPPS.SSU1 enhanced the GPP synthase activities of PtGPPS1.LSU and PtGPPS2.LSU in vitro. Altogether, our data suggest that PtGPPS1.LSU and PtGPPS2.LSU in combination with PtGPPS.SSU1 may provide the substrate for herbivory-induced monoterpene formation in P. trichocarpa. The sole FPP synthase PtFPPS1 likely produces FPP for both primary and specialized metabolism in this plant species.
    Subject(s): Biochemistry & Molecular Biology ; Physical Sciences ; Chemistry ; Life Sciences & Biomedicine ; Chemistry, Multidisciplinary ; Science & Technology ; Up-Regulation ; Populus - chemistry ; Herbivory ; Populus - genetics ; Gene Expression Regulation, Enzymologic ; Plant Proteins - genetics ; Terpenes - chemistry ; Populus - enzymology ; Animals ; Dimethylallyltranstransferase - genetics ; Gene Expression Regulation, Plant ; Dimethylallyltranstransferase - metabolism ; Insecta - physiology ; Plant Proteins - metabolism ; Volatile Organic Compounds - chemistry ; monoterpene ; prenyl transferase ; Populus trichocarpa ; sesquiterpene ; isoprenyl diphosphate synthase ; volatile organic compound (VOC) ; Lymantria dispar
    ISSN: 1420-3049
    E-ISSN: 1420-3049
    Source: Academic Search Ultimate
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 7
    Language: English
    In: Scientific reports, 2019-05-22, Vol.9 (1), p.7714-7714
    Description: Herbivory is well known to trigger increased emission of volatile organic compounds (VOCs) from plants, but we know little about the responses of mature trees. We measured the volatiles emitted by leaves of old-growth black poplar (Populus nigra) trees after experimental damage by gypsy moth (Lymantria dispar) caterpillars in a floodplain forest, and studied the effect of herbivory on the transcript abundance of two genes involved in the biosynthesis of VOCs, and the accumulation of defence phytohormones. Herbivory significantly increased volatile emission from the experimentally damaged foliage, but not from adjacent undamaged leaves in the damaged branches (i.e., no systemic response). Methyl butyraldoximes, 4,8-dimethyl-1,3,7-nonatriene (DMNT), (Z)-3-hexenol and (E)-beta-ocimene, amongst other compounds, were found to be important in distinguishing the blend of herbivore-damaged vs. undamaged leaves. Herbivory also increased expression of PnTPS3 (described here for the first time) and PnCYP79D6-v4 genes at the damaged sites, these genes encode for an (E)-beta-ocimene synthase and a P450 enzyme involved in aldoxime formation, respectively, demonstrating de novo biosynthesis of the volatiles produced. Herbivore-damaged leaves had significantly higher levels of jasmonic acid and its conjugate (-)-jasmonic acid-isoleucine. This study shows that mature trees in the field have a robust response to herbivory, producing induced volatiles at the damaged sites even after previous natural herbivory and under changing environmental conditions, however, further studies are needed to establish whether the observed absence of systemic responses is typical of mature poplar trees or if specific conditions are required for their induction.
    Subject(s): Science & Technology - Other Topics ; Multidisciplinary Sciences ; Science & Technology ; Genes, Plant ; Volatile Organic Compounds - analysis ; Feeding Behavior ; Herbivory ; Oxylipins - analysis ; Populus - genetics ; Populus - physiology ; Moths - growth & development ; Plant Proteins - genetics ; Animals ; Larva ; Plant Leaves - metabolism ; Cyclopentanes - analysis ; Plant Proteins - metabolism ; Trees ; Transcription ; Branches ; Floodplains ; Biosynthesis ; Volatiles ; Allelochemicals ; Environmental conditions ; Leaves ; Ocimene ; Foliage ; Volatile organic compounds--VOCs ; Herbivores ; Jasmonic acid ; Organic compounds ; Isoleucine
    ISSN: 2045-2322
    E-ISSN: 2045-2322
    Source: Nature Open Access
    Source: Academic Search Ultimate
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: PubMed Central
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  • 8
    Language: English
    In: BMC plant biology, 2016-10-04, Vol.16 (1), p.215-215
    Description: Amino acid-derived aldoximes and nitriles play important roles in plant defence. They are well-known as precursors for constitutive defence compounds such as cyanogenic glucosides and glucosinolates, but are also released as volatiles after insect feeding. Cytochrome P450 monooxygenases (CYP) of the CYP79 family catalyze the formation of aldoximes from the corresponding amino acids. However, the majority of CYP79s characterized so far are involved in cyanogenic glucoside or glucosinolate biosynthesis and only a few have been reported to be responsible for nitrogenous volatile production. In this study we analysed and compared the jasmonic acid-induced volatile blends of two Erythroxylum species, the cultivated South American crop species E. coca and the African wild species E. fischeri. Both species produced different nitrogenous compounds including aliphatic aldoximes and an aromatic nitrile. Four isolated CYP79 genes (two from each species) were heterologously expressed in yeast and biochemically characterized. CYP79D62 from E. coca and CYP79D61 and CYP79D60 from E. fischeri showed broad substrate specificity in vitro and converted L-phenylalanine, L-isoleucine, L-leucine, L-tryptophan, and L-tyrosine into the respective aldoximes. In contrast, recombinant CYP79D63 from E. coca exclusively accepted L-tryptophan as substrate. Quantitative real-time PCR revealed that CYP79D60, CYP79D61, and CYP79D62 were significantly upregulated in jasmonic acid-treated Erythroxylum leaves. The kinetic parameters of the enzymes expressed in vitro coupled with the expression patterns of the corresponding genes and the accumulation and emission of (E/Z)-phenylacetaldoxime, (E/Z)-indole-3-acetaldoxime, (E/Z)-3-methylbutyraldoxime, and (E/Z)-2-methylbutyraldoxime in jasmonic acid-treated leaves suggest that CYP79D60, CYP79D61, and CYP79D62 accept L-phenylalanine, L-leucine, L-isoleucine, and L-tryptophan as substrates in vivo and contribute to the production of volatile and semi-volatile nitrogenous defence compounds in E. coca and E. fischeri.
    Subject(s): Amino Acid Sequence ; Species Specificity ; Volatile Organic Compounds - metabolism ; Nitrogen Compounds - metabolism ; Cytochrome P-450 Enzyme System - metabolism ; Coca - genetics ; Phylogeny ; Coca - metabolism ; Oxylipins - metabolism ; Plant Proteins - genetics ; Coca - enzymology ; Cytochrome P-450 Enzyme System - chemistry ; Sequence Alignment ; Oximes - metabolism ; Plant Proteins - chemistry ; Cytochrome P-450 Enzyme System - genetics ; Cyclopentanes - metabolism ; Plant Proteins - metabolism ; Real-Time Polymerase Chain Reaction ; Volatile organic compounds ; Cytochrome P-450 ; Physiological aspects ; Coca ; Genetic aspects ; Research ; Jasmonates ; Aldoxime ; CYP79 ; Volatiles ; Erythroxylum ; Cytochrome P450 monooxygenase
    ISSN: 1471-2229
    E-ISSN: 1471-2229
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 9
    Language: English
    In: BMC plant biology, 2018-10-22, Vol.18 (1), p.251-12
    Description: Nitrilases are nitrile-converting enzymes commonly found within the plant kingdom that play diverse roles in nitrile detoxification, nitrogen recycling, and phytohormone biosynthesis. Although nitrilases are present in all higher plants, little is known about their function in trees. Upon herbivory, poplars produce considerable amounts of toxic nitriles such as benzyl cyanide, 2-methylbutyronitrile, and 3-methylbutyronitrile. In addition, as byproduct of the ethylene biosynthetic pathway upregulated in many plant species after herbivory, toxic β-cyanoalanine may accumulate in damaged poplar leaves. In this work, we studied the nitrilase gene family in Populus trichocarpa and investigated the potential role of the nitrilase PtNIT1 in the catabolism of herbivore-induced nitriles. A BLAST analysis revealed three putative nitrilase genes (PtNIT1, PtNIT2, PtNIT3) in the genome of P. trichocarpa. While PtNIT1 was expressed in poplar leaves and showed increased transcript accumulation after leaf herbivory, PtNIT2 and PtNIT3 appeared not to be expressed in undamaged or herbivore-damaged leaves. Recombinant PtNIT1 produced in Escherichia coli accepted biogenic nitriles such as β-cyanoalanine, benzyl cyanide, and indole-3-acetonitrile as substrates in vitro and converted them into the corresponding acids. In addition to this nitrilase activity, PtNIT1 showed nitrile hydratase activity towards β-cyanoalanine, resulting in the formation of the amino acid asparagine. The kinetic parameters of PtNIT1 suggest that the enzyme utilizes β-cyanoalanine and benzyl cyanide as substrates in vivo. Indeed, β-cyanoalanine and benzyl cyanide were found to accumulate in herbivore-damaged poplar leaves. The upregulation of ethylene biosynthesis genes after leaf herbivory indicates that herbivore-induced β-cyanoalanine accumulation is likely caused by ethylene formation. Our data suggest a role for PtNIT1 in the catabolism of herbivore-induced β-cyanoalanine and benzyl cyanide in poplar leaves.
    Subject(s): Biological research ; Enzymes ; Physiological aspects ; Poplar ; Nitriles ; Hydrolases ; Genetic aspects ; Research ; Plant-animal interactions ; Biology, Experimental ; Analysis ; Escherichia coli ; Ethylene ; Asparagine ; Explosions ; Benzyl cyanide ; Populus trichocarpa ; NIT1 ; Plant defense ; β-Cyanoalanine ; Nitrilase
    ISSN: 1471-2229
    E-ISSN: 1471-2229
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 10
    Language: English
    In: The Plant journal : for cell and molecular biology, 2014-12, Vol.80 (6), p.1095-1107
    Description: Summary Numerous plant species emit volatile nitriles upon herbivory, but the biosynthesis as well as the relevance of these nitrogenous compounds in plant–insect interactions remains unknown. Populus trichocarpa has been shown to produce a complex blend of nitrogenous volatiles, including aldoximes and nitriles, after herbivore attack. The aldoximes were previously reported to be derived from amino acids by the action of cytochrome P450 enzymes of the CYP79 family. Here we show that nitriles are derived from aldoximes by another type of P450 enzyme in P. trichocarpa. First, feeding of deuterium‐labeled phenylacetaldoxime to poplar leaves resulted in incorporation of the label into benzyl cyanide, demonstrating that poplar volatile nitriles are derived from aldoximes. Then two P450 enzymes, CYP71B40v3 and CYP71B41v2, were characterized that produce aliphatic and aromatic nitriles from their respective aldoxime precursors. Both possess typical P450 sequence motifs but do not require added NADPH or cytochrome P450 reductase for catalysis. Since both enzymes are expressed after feeding by gypsy moth caterpillars, they are likely to be involved in herbivore‐induced volatile nitrile emission in P. trichocarpa. Olfactometer experiments showed that these volatile nitriles have a strong repellent activity against gypsy moth caterpillars, suggesting they play a role in induced direct defense against poplar herbivores. Significance Statement Our work provides evidence for the function of CYP71 genes in the formation of volatile nitriles, which are known from a large number of plant species as floral compounds or herbivore‐ and pathogen‐induced substances. Moreover, we present evidence for the function of nitriles in induced direct defense against insect herbivores.
    Subject(s): nitriles ; direct defense ; cytochrome P450 ; Populus trichocarpa ; CYP71 ; volatiles ; Nitriles - metabolism ; Populus - immunology ; Volatile Organic Compounds - metabolism ; Cytochrome P-450 Enzyme System - metabolism ; Herbivory ; Populus - genetics ; Phylogeny ; Sequence Analysis, DNA ; Plant Leaves - immunology ; Oximes - chemistry ; Plant Proteins - genetics ; Populus - enzymology ; Volatile Organic Compounds - pharmacology ; Animals ; Larva ; Plant Leaves - genetics ; Oximes - metabolism ; Gene Expression Regulation, Plant ; Cytochrome P-450 Enzyme System - genetics ; Moths - physiology ; Plant Proteins - metabolism ; Plant Leaves - enzymology ; Moths - drug effects ; Enzymes ; Gypsy moth ; Physiological aspects ; Amino acids ; Nitriles ; Catalysis ; Moths
    ISSN: 0960-7412
    E-ISSN: 1365-313X
    Source: Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals
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