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Heiko Rischer - One of the best experts on this subject based on the ideXlab platform.
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Elicitation of furanocoumarins in poison hemlock (Conium maculatum L.) cell culture
Plant Cell Tissue and Organ Culture (PCTOC), 2015Co-Authors: Philipp Meier, Hannu Hotti, Heiko RischerAbstract:Furanocoumarins, such as psoralen, xanthotoxin and bergapten, serve as protectants against phytopathogens and are used in pharmaceutical applications e.g. as DNA-crosslinking agents against non-melanoma skin cancers. Poison hemlock plants ( Conium maculatum L.) are a known source of furanocoumarins and toxic alkaloids, but systematic research on callus and suspension cultures with the aim of eliciting secondary metabolites is lacking. Therefore callus cultures of poison hemlock were induced with 0.186 mg L^−1 6-benzylaminopurine and 2 or 4 mg L^−1 naphthalene acetic acid on McCown’s Woody plant medium. A broad variety of elicitors (alginic acid, cellulase, chitosan, ethylene, methyl jasmonate, salicylic acid, copper(II) sulphate and silver nitrate) were tested with an established cell suspension culture for their capacity to trigger differential metabolite accumulation. Samples were extracted and analysed by gas chromatography-mass spectrometry. Elicitation with alginic acid, cellulase, chitosan, silver nitrate and copper(II) sulphate induced furanocoumarins. Plant hormones (ethylene, methyl jasmonate and salicylic acid) were not able to induce furanocoumarins. Extracts contained bergapten, columbianetin, isopimpinellin, marmesin, oroselone, psoralen and xanthotoxin but not piperidine alkaloids. The relative amount of furanocoumarins was generally higher in the medium than in the cells. The report describes the angular furanocoumarins oroselone and columbianetin together with the linear furanocoumarin marmesin, elicited for the first time in poison hemlock.
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Polyketide synthases from poison hemlock (Conium maculatum L.)
FEBS Journal, 2015Co-Authors: Hannu Hotti, Mikko Arvas, Teemu H. Teeri, Tuulikki Seppänen-laakso, Heiko RischerAbstract:Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs. Database Nucleotide sequence data are available in GenBank/EMBL/DDBJ under the accession numbers KP726914, KP726915, KP726916, KP726917, KP726918, and KP726919
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Polyketide synthases from poison hemlock (Conium maculatum L.).
The FEBS journal, 2015Co-Authors: Hannu Hotti, Mikko Arvas, Teemu H. Teeri, Tuulikki Seppänen-laakso, Heiko RischerAbstract:Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs.
May R. Berenbaum - One of the best experts on this subject based on the ideXlab platform.
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Host plant selection by a monophagous herbivore is not mediated by quantitative changes in unique plant chemistry: Agonopterix alstroemeriana and Conium maculatum
Arthropod-Plant Interactions, 2008Co-Authors: Eva Castells, May R. BerenbaumAbstract:Host plant selection by ovipositing females is a key process determining the success of phytophagous insects. In oligophagous lepidopterans, host-specific plant secondary chemicals are expected to be dominant factors governing oviposition behavior; distinctive compounds can serve as high-contrast signals that clearly differentiate confamilial hosts from non-hosts increasing the accuracy of host quality evaluation. Agonopterix alstroemeriana (Clerk) (Lepidoptera: Oecophoridae) and Conium maculatum L. (Apiaceae) form an extremely specialized plant-herbivore system, with A. alstroemeriana monophagous on C. maculatum , a plant with few other insect herbivores at least in part due to its virtually unique capacity among plants to produce piperidine alkaloids. Here we have studied the response of A. alstroemeriana oviposition to unique host plant secondary metabolites, piperidine alkaloids, and widespread compounds, mono- and sesquiterpenes, in a concentration-dependent fashion. Rates of oviposition were negatively correlated with Z -ocimene concentrations. To confirm the deterrent properties of this monoterpene for A. alstroemeriana oviposition, we conducted a choice experiment using artificially damaged C. maculatum plants, with higher emission of volatiles, and undamaged control plants. Damaged plants were less preferred as oviposition sites compared to the controls. The lack of association between oviposition and piperidine alkaloids, defenses unique to Conium species, suggests that quantitative changes of these species-specific chemicals do not play a predominant role in host selection by the monophagous A. alstroemeriana .
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Resistance of the generalist moth Trichoplusia ni (Noctuidae) to a novel chemical defense in the invasive plant Conium maculatum
Chemoecology, 2008Co-Authors: Eva Castells, May R. BerenbaumAbstract:Conium maculatum is an apiaceous species native to Eurasia that is highly toxic to vertebrates due to the presence of piperidine alkaloids, including coniine and γ-coniceine. More than 200 years after invading the United States this species remains mostly free from generalist insect herbivores. The presence of novel chemical defenses in the introduced range could provide invasive species with a competitive advantage relative to native plants. The cabbage looper ( Trichoplusia ni ) is a generalist lepidopteran found throughout the US that occasionally feeds on C. maculatum . We evaluated the toxicity of piperidine alkaloids to T. ni and determined putative resistance mechanisms, both behavioral and physiological, that allows this insect to develop successfully on C. maculatum foliage. T. ni larvae raised on diets enriched with coniine and γ-coniceine showed a decrease in consumption and longer development time, but no effects on growth were found at any alkaloid concentration. In a diet choice experiment T. ni larvae showed no avoidance of alkaloid-enriched diets, suggesting that the deterrence produced by alkaloids was related to a post-ingestive metabolic response. The ability of T. ni to consume diets high in alkaloid content could be due to at least three different mechanisms: 1) a decreased consumption rate, 2) efficient excretion of at least 1/3 of ingested alkaloids unmetabolized in frass, and 3) partial detoxification of alkaloids by cytochrome P450 s, as shown by the decreased larval growth in the presence of piperonyl butoxide, a P450 inhibitor. Even though T. ni tolerates C. maculatum alkaloids, the use of this species as a host plant could be ecologically disadvantageous due to prolonged larval growth and thus increased exposure to predators. Novel plant secondary compounds do not guarantee increased resistance to generalist herbivores.
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Laboratory rearing of Agonopterix alstroemeriana, the defoliating poison hemlock (Conium maculatum L.) moth, and effects of piperidine alkaloids on preference and performance.
Environmental Entomology, 2006Co-Authors: Eva Castells, May R. BerenbaumAbstract:Conium maculatum L. (Apiaceae), or poison hemlock, is an invasive plant native to Europe that has become extensively naturalized throughout North America. This species contains piperidine alkaloids, including coniine and γ-coniceine, that are highly toxic to vertebrates. C. maculatum was relatively free from herbivores in North America until the accidental introduction 30 yr ago of its monophagous European associate Agonopterix alstroemeriana (Clerck) (Lepidoptera: Oecophoridae). At present, A. alstroemeriana is widespread across the United States, and in some areas, such as the Northwest, can inflict substantial damage on its host plant, leading to desiccation and death. A. alstroemeriana has been used in recent years for the biological control of C. maculatum, although its use has been limited by the availability of larvae, which are field-collected from early to mid-spring, and by the lack of available information about its life history and feeding habits. Here we describe a laboratory-rearing protocol incorporating a simulated winter to induce diapause and a semidefined artificial diet that allows the production of multiple generations per year and enabled us to determine the number and duration of A. alstroemeriana developmental stages. The development of the artificial diet also permitted studies of preference and performance of A. alstroemeriana in relation to hostplant chemistry. Rearing A. alstroemeriana on artificial diet supplemented with 1.5% DW coniine had no adverse impact on ultimate instar growth or performance. In a feeding behavior assay, the presence of coniine in the diet increased A. alstroemeriana consumption three-fold relative to control diet. This behavioral response contrasts dramatically with that of Agonopterix clemensella, a native Apiaceae specialist that does not use C. maculatum as a host; of 30 larvae tested, 29 fed exclusively on diets lacking supplemental coniine. The rearing protocol and artificial diet presented here can facilitate further studies of ecological and evolutionary responses of C. maculatum after its reassociation with a coevolved herbivore in North America.
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Laboratory rearing of Agonopterix alstroemeriana, the defoliating poison hemlock (Conium maculatum L.) moth, and effects of piperidine alkaloids on preference and performance.
Environmental Entomology, 2006Co-Authors: Eva Castells, May R. BerenbaumAbstract:Conium maculatum L. (Apiaceae), or poison hemlock, is an invasive plant native to Europe that has become extensively naturalized throughout North America. This species contains piperidine alkaloids, including coniine and γ-coniceine, that are highly toxic to vertebrates. C. maculatum was relatively free from herbivores in North America until the accidental introduction 30 yr ago of its monophagous European associate Agonopterix alstroemeriana (Clerck) (Lepidoptera: Oecophoridae). At present, A. alstroemeriana is widespread across the United States, and in some areas, such as the Northwest, can inflict substantial damage on its host plant, leading to desiccation and death. A. alstroemeriana has been used in recent years for the biological control of C. maculatum, although its use has been limited by the availability of larvae, which are field-collected from early to mid-spring, and by the lack of available information about its life history and feeding habits. Here we describe a laboratory-rearing protocol incorporating a simulated winter to induce diapause and a semidefined artificial diet that allows the production of multiple generations per year and enabled us to determine the number and duration of A. alstroemeriana developmental stages. The development of the artificial diet also permitted studies of preference and performance of A. alstroemeriana in relation to hostplant chemistry. Rearing A. alstroemeriana on artificial diet supplemented with 1.5% DW coniine had no adverse impact on ultimate instar growth or performance. In a feeding behavior assay, the presence of coniine in the diet increased A. alstroemeriana consumption three-fold relative to control diet. This behavioral response contrasts dramatically with that of Agonopterix clemensella, a native Apiaceae specialist that does not use C. maculatum as a host; of 30 larvae tested, 29 fed exclusively on diets lacking supplemental coniine. The rearing protocol and artificial diet presented here can facilitate further studies of ecological and evolutionary responses of C. maculatum after its reassociation with a coevolved herbivore in North America.
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Genetic variation of alkaloid production in Conium maculatum after reassociation with the specialist moth Agonopterix alstroemeriana
2006Co-Authors: Eva Castells, May R. BerenbaumAbstract:Studies in biological control and invasion biology rarely determine whether introduced plants may rapidly evolve in the area of introduction. Examining the evolution of plant chemical defenses after reassociation with a coevolved enemy is important not only to understand the dynamics of plant-herbivore interactions but also in predicting potential ultimate outcomes of classical weed control programs. A system in which chemical evolution may be examined involves the interaction between Conium maculatum, a Eurasian weed naturalized in North America that contains high concentrations of piperidine alkaloids (γ-coniceine, coniine, conhydrinone) acting as chemical defenses, and its monophagous European associate Agonopterix alstroemeriana. In the United States, C. maculatum was largely free from herbivory until approximately 30 years ago when it was reassociated via accidental introduction with A. alstroemeriana. At present C. maculatum and A. alstroemeriana are found in a continuum of re-association times and intensities. To determine the degree to which variation in alkaloid content and resistance to A. alstroemeriana were genetically based we conducted a common garden experiment involving plants from three locations in the U.S. (Illinois, Washington and New York) that had experienced 12, 20 and 32 years of reassociation with A. alstroemeriana respectively. We analyzed alkaloid concentrations and recorded the natural colonization of A. alstroemeriana on C. maculatum by counting the number of leaf rolls at the end of the season. Additionally, a bioassay with larvae from our laboratory colony raised on IL, NY and WA foliage was conducted to determine the effects of secondary chemistry on insect fitness.
Hannu Hotti - One of the best experts on this subject based on the ideXlab platform.
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Elicitation of furanocoumarins in poison hemlock (Conium maculatum L.) cell culture
Plant Cell Tissue and Organ Culture (PCTOC), 2015Co-Authors: Philipp Meier, Hannu Hotti, Heiko RischerAbstract:Furanocoumarins, such as psoralen, xanthotoxin and bergapten, serve as protectants against phytopathogens and are used in pharmaceutical applications e.g. as DNA-crosslinking agents against non-melanoma skin cancers. Poison hemlock plants ( Conium maculatum L.) are a known source of furanocoumarins and toxic alkaloids, but systematic research on callus and suspension cultures with the aim of eliciting secondary metabolites is lacking. Therefore callus cultures of poison hemlock were induced with 0.186 mg L^−1 6-benzylaminopurine and 2 or 4 mg L^−1 naphthalene acetic acid on McCown’s Woody plant medium. A broad variety of elicitors (alginic acid, cellulase, chitosan, ethylene, methyl jasmonate, salicylic acid, copper(II) sulphate and silver nitrate) were tested with an established cell suspension culture for their capacity to trigger differential metabolite accumulation. Samples were extracted and analysed by gas chromatography-mass spectrometry. Elicitation with alginic acid, cellulase, chitosan, silver nitrate and copper(II) sulphate induced furanocoumarins. Plant hormones (ethylene, methyl jasmonate and salicylic acid) were not able to induce furanocoumarins. Extracts contained bergapten, columbianetin, isopimpinellin, marmesin, oroselone, psoralen and xanthotoxin but not piperidine alkaloids. The relative amount of furanocoumarins was generally higher in the medium than in the cells. The report describes the angular furanocoumarins oroselone and columbianetin together with the linear furanocoumarin marmesin, elicited for the first time in poison hemlock.
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Polyketide synthases from poison hemlock (Conium maculatum L.)
FEBS Journal, 2015Co-Authors: Hannu Hotti, Mikko Arvas, Teemu H. Teeri, Tuulikki Seppänen-laakso, Heiko RischerAbstract:Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs. Database Nucleotide sequence data are available in GenBank/EMBL/DDBJ under the accession numbers KP726914, KP726915, KP726916, KP726917, KP726918, and KP726919
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Polyketide synthases from poison hemlock (Conium maculatum L.).
The FEBS journal, 2015Co-Authors: Hannu Hotti, Mikko Arvas, Teemu H. Teeri, Tuulikki Seppänen-laakso, Heiko RischerAbstract:Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs.
Eva Castells - One of the best experts on this subject based on the ideXlab platform.
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Host plant selection by a monophagous herbivore is not mediated by quantitative changes in unique plant chemistry: Agonopterix alstroemeriana and Conium maculatum
Arthropod-Plant Interactions, 2008Co-Authors: Eva Castells, May R. BerenbaumAbstract:Host plant selection by ovipositing females is a key process determining the success of phytophagous insects. In oligophagous lepidopterans, host-specific plant secondary chemicals are expected to be dominant factors governing oviposition behavior; distinctive compounds can serve as high-contrast signals that clearly differentiate confamilial hosts from non-hosts increasing the accuracy of host quality evaluation. Agonopterix alstroemeriana (Clerk) (Lepidoptera: Oecophoridae) and Conium maculatum L. (Apiaceae) form an extremely specialized plant-herbivore system, with A. alstroemeriana monophagous on C. maculatum , a plant with few other insect herbivores at least in part due to its virtually unique capacity among plants to produce piperidine alkaloids. Here we have studied the response of A. alstroemeriana oviposition to unique host plant secondary metabolites, piperidine alkaloids, and widespread compounds, mono- and sesquiterpenes, in a concentration-dependent fashion. Rates of oviposition were negatively correlated with Z -ocimene concentrations. To confirm the deterrent properties of this monoterpene for A. alstroemeriana oviposition, we conducted a choice experiment using artificially damaged C. maculatum plants, with higher emission of volatiles, and undamaged control plants. Damaged plants were less preferred as oviposition sites compared to the controls. The lack of association between oviposition and piperidine alkaloids, defenses unique to Conium species, suggests that quantitative changes of these species-specific chemicals do not play a predominant role in host selection by the monophagous A. alstroemeriana .
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Resistance of the generalist moth Trichoplusia ni (Noctuidae) to a novel chemical defense in the invasive plant Conium maculatum
Chemoecology, 2008Co-Authors: Eva Castells, May R. BerenbaumAbstract:Conium maculatum is an apiaceous species native to Eurasia that is highly toxic to vertebrates due to the presence of piperidine alkaloids, including coniine and γ-coniceine. More than 200 years after invading the United States this species remains mostly free from generalist insect herbivores. The presence of novel chemical defenses in the introduced range could provide invasive species with a competitive advantage relative to native plants. The cabbage looper ( Trichoplusia ni ) is a generalist lepidopteran found throughout the US that occasionally feeds on C. maculatum . We evaluated the toxicity of piperidine alkaloids to T. ni and determined putative resistance mechanisms, both behavioral and physiological, that allows this insect to develop successfully on C. maculatum foliage. T. ni larvae raised on diets enriched with coniine and γ-coniceine showed a decrease in consumption and longer development time, but no effects on growth were found at any alkaloid concentration. In a diet choice experiment T. ni larvae showed no avoidance of alkaloid-enriched diets, suggesting that the deterrence produced by alkaloids was related to a post-ingestive metabolic response. The ability of T. ni to consume diets high in alkaloid content could be due to at least three different mechanisms: 1) a decreased consumption rate, 2) efficient excretion of at least 1/3 of ingested alkaloids unmetabolized in frass, and 3) partial detoxification of alkaloids by cytochrome P450 s, as shown by the decreased larval growth in the presence of piperonyl butoxide, a P450 inhibitor. Even though T. ni tolerates C. maculatum alkaloids, the use of this species as a host plant could be ecologically disadvantageous due to prolonged larval growth and thus increased exposure to predators. Novel plant secondary compounds do not guarantee increased resistance to generalist herbivores.
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Laboratory rearing of Agonopterix alstroemeriana, the defoliating poison hemlock (Conium maculatum L.) moth, and effects of piperidine alkaloids on preference and performance.
Environmental Entomology, 2006Co-Authors: Eva Castells, May R. BerenbaumAbstract:Conium maculatum L. (Apiaceae), or poison hemlock, is an invasive plant native to Europe that has become extensively naturalized throughout North America. This species contains piperidine alkaloids, including coniine and γ-coniceine, that are highly toxic to vertebrates. C. maculatum was relatively free from herbivores in North America until the accidental introduction 30 yr ago of its monophagous European associate Agonopterix alstroemeriana (Clerck) (Lepidoptera: Oecophoridae). At present, A. alstroemeriana is widespread across the United States, and in some areas, such as the Northwest, can inflict substantial damage on its host plant, leading to desiccation and death. A. alstroemeriana has been used in recent years for the biological control of C. maculatum, although its use has been limited by the availability of larvae, which are field-collected from early to mid-spring, and by the lack of available information about its life history and feeding habits. Here we describe a laboratory-rearing protocol incorporating a simulated winter to induce diapause and a semidefined artificial diet that allows the production of multiple generations per year and enabled us to determine the number and duration of A. alstroemeriana developmental stages. The development of the artificial diet also permitted studies of preference and performance of A. alstroemeriana in relation to hostplant chemistry. Rearing A. alstroemeriana on artificial diet supplemented with 1.5% DW coniine had no adverse impact on ultimate instar growth or performance. In a feeding behavior assay, the presence of coniine in the diet increased A. alstroemeriana consumption three-fold relative to control diet. This behavioral response contrasts dramatically with that of Agonopterix clemensella, a native Apiaceae specialist that does not use C. maculatum as a host; of 30 larvae tested, 29 fed exclusively on diets lacking supplemental coniine. The rearing protocol and artificial diet presented here can facilitate further studies of ecological and evolutionary responses of C. maculatum after its reassociation with a coevolved herbivore in North America.
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Laboratory rearing of Agonopterix alstroemeriana, the defoliating poison hemlock (Conium maculatum L.) moth, and effects of piperidine alkaloids on preference and performance.
Environmental Entomology, 2006Co-Authors: Eva Castells, May R. BerenbaumAbstract:Conium maculatum L. (Apiaceae), or poison hemlock, is an invasive plant native to Europe that has become extensively naturalized throughout North America. This species contains piperidine alkaloids, including coniine and γ-coniceine, that are highly toxic to vertebrates. C. maculatum was relatively free from herbivores in North America until the accidental introduction 30 yr ago of its monophagous European associate Agonopterix alstroemeriana (Clerck) (Lepidoptera: Oecophoridae). At present, A. alstroemeriana is widespread across the United States, and in some areas, such as the Northwest, can inflict substantial damage on its host plant, leading to desiccation and death. A. alstroemeriana has been used in recent years for the biological control of C. maculatum, although its use has been limited by the availability of larvae, which are field-collected from early to mid-spring, and by the lack of available information about its life history and feeding habits. Here we describe a laboratory-rearing protocol incorporating a simulated winter to induce diapause and a semidefined artificial diet that allows the production of multiple generations per year and enabled us to determine the number and duration of A. alstroemeriana developmental stages. The development of the artificial diet also permitted studies of preference and performance of A. alstroemeriana in relation to hostplant chemistry. Rearing A. alstroemeriana on artificial diet supplemented with 1.5% DW coniine had no adverse impact on ultimate instar growth or performance. In a feeding behavior assay, the presence of coniine in the diet increased A. alstroemeriana consumption three-fold relative to control diet. This behavioral response contrasts dramatically with that of Agonopterix clemensella, a native Apiaceae specialist that does not use C. maculatum as a host; of 30 larvae tested, 29 fed exclusively on diets lacking supplemental coniine. The rearing protocol and artificial diet presented here can facilitate further studies of ecological and evolutionary responses of C. maculatum after its reassociation with a coevolved herbivore in North America.
-
Genetic variation of alkaloid production in Conium maculatum after reassociation with the specialist moth Agonopterix alstroemeriana
2006Co-Authors: Eva Castells, May R. BerenbaumAbstract:Studies in biological control and invasion biology rarely determine whether introduced plants may rapidly evolve in the area of introduction. Examining the evolution of plant chemical defenses after reassociation with a coevolved enemy is important not only to understand the dynamics of plant-herbivore interactions but also in predicting potential ultimate outcomes of classical weed control programs. A system in which chemical evolution may be examined involves the interaction between Conium maculatum, a Eurasian weed naturalized in North America that contains high concentrations of piperidine alkaloids (γ-coniceine, coniine, conhydrinone) acting as chemical defenses, and its monophagous European associate Agonopterix alstroemeriana. In the United States, C. maculatum was largely free from herbivory until approximately 30 years ago when it was reassociated via accidental introduction with A. alstroemeriana. At present C. maculatum and A. alstroemeriana are found in a continuum of re-association times and intensities. To determine the degree to which variation in alkaloid content and resistance to A. alstroemeriana were genetically based we conducted a common garden experiment involving plants from three locations in the U.S. (Illinois, Washington and New York) that had experienced 12, 20 and 32 years of reassociation with A. alstroemeriana respectively. We analyzed alkaloid concentrations and recorded the natural colonization of A. alstroemeriana on C. maculatum by counting the number of leaf rolls at the end of the season. Additionally, a bioassay with larvae from our laboratory colony raised on IL, NY and WA foliage was conducted to determine the effects of secondary chemistry on insect fitness.
Teemu H. Teeri - One of the best experts on this subject based on the ideXlab platform.
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Polyketide synthases from poison hemlock (Conium maculatum L.)
FEBS Journal, 2015Co-Authors: Hannu Hotti, Mikko Arvas, Teemu H. Teeri, Tuulikki Seppänen-laakso, Heiko RischerAbstract:Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs. Database Nucleotide sequence data are available in GenBank/EMBL/DDBJ under the accession numbers KP726914, KP726915, KP726916, KP726917, KP726918, and KP726919
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Polyketide synthases from poison hemlock (Conium maculatum L.).
The FEBS journal, 2015Co-Authors: Hannu Hotti, Mikko Arvas, Teemu H. Teeri, Tuulikki Seppänen-laakso, Heiko RischerAbstract:Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs.