The Experts below are selected from a list of 2022 Experts worldwide ranked by ideXlab platform
Loren H Rieseberg - One of the best experts on this subject based on the ideXlab platform.
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transcriptome divergence between introduced and native populations of canada thistle Cirsium arvense
2013Co-Authors: Alessia Guggisberg, Loren H Rieseberg, Jie HuangAbstract:Summary Introduced plants may quickly evolve new adaptive traits upon their introduction. Canada thistle (Cirsium arvense – Cardueae, Asteraceae) is one of the worst invasive weeds worldwide. The goal of this study is to compare gene expression profiles of native (European) and introduced (North American) populations of this species, to elucidate the genetic mechanisms that may underlie such rapid adaptation. We explored the transcriptome of ten populations (five per range) of C. arvense in response to three treatments (control, nutrient deficiency and shading) using a customized microarray chip containing 63 690 expressed sequence tags (ESTs), and verified the expression level of 13 loci through real-time quantitative PCR. Only 2116 ESTs (3.5%) were found to be differentially expressed between the ranges, and 4458 ESTs (7.1%) exhibited a significant treatment-by-range effect. Among them was an overrepresentation of loci involved in stimulus and stress responses. Cirsium arvense has evolved different life history strategies on each continent. The two ranges notably differ with regard to R-protein mediated defence, sensitivity to abiotic stresses, and developmental timing. The fact that genotypes from the Midwest exhibit different expression kinetics than remaining North American samples further corroborates the hypothesis that the New World has been colonized twice, independently.
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invasion history of north american canada thistle Cirsium arvense
2012Co-Authors: Alessia Guggisberg, David P Horvath, Michael E. Foley, Loren H Rieseberg, Erik Welk, R Sforza, James V AndersonAbstract:Aim Canada thistle (Cirsium arvense– Cardueae, Asteraceae) is one of the worst invasive plants world-wide. Native to Eurasia, its unintentional introduction into North America now threatens the native flora and is responsible for enormous agricultural losses. The goals of this study are to: (1) reconstruct the evolutionary history of C. arvense and estimate how often it may have colonized North America, (2) compare the genetic diversity between European and North American populations to detect signs of demographic bottlenecks and/or patterns of population admixture, and (3) conduct bioclimatic comparisons to infer eventual niche shifts following this species’ introduction into North America. Location Europe and North America. Methods A total of 1522 individuals from 58 populations were investigated with six microsatellite markers. Estimates of heterozygosity (HE) and allelic richness (RS) were quantified for each population, and population structure was inferred via analyses of molecular variance (AMOVAs), principal components analyses (PCAs), Mantel tests and Bayesian clustering analyses. Climatic niche spaces were based on 19 bioclimatic variables extracted from approximately 32,000 locations covering the entire range, and compared using PCA and hierarchical cluster analysis. Results Although there is evidence of multiple introductions from divergent European lineages, North American populations of C. arvense exhibited significantly lower levels of genetic diversity than their putative ancestors. Bioclimatic comparisons pointed to a high degree of niche conservatism during invasion, but indicated that genotypes from the former USSR and Central European mountain chains were probably best adapted to invade North America upon entry into the continent. Main conclusions Genetic and historical data suggest that C. arvense first entered North America from Western Europe with the first European settlers, and was later introduced from Eastern Europe into the prairie states during the agricultural boom. The species went through a significant bottleneck following its introduction into the New World, but the level of genetic diversity remained high owing to admixture between genetically differentiated lineages and to a highly efficient outcrossing breeding system.
Sven Bacher - One of the best experts on this subject based on the ideXlab platform.
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Establishing systemic rust infections in Cirsium arvense in the field
2008Co-Authors: Heiri Wandeler, Wolfgang Nentwig, Sven BacherAbstract:Abstract An existing method to induce systemic rust infections in creeping thistles (Cirsium arvense) using an insect vector, the weevil Ceratapion onopordi, was successfully applied in the field. Urediniospores of Puccinia punctiformis were experimentally transmitted to naturally grown thistles, to our knowledge for the first time resulting in systemically infected shoots in an established thistle population.
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insect transmitted urediniospores of the rust puccinia punctiformis cause systemic infections in established Cirsium arvense plants
2006Co-Authors: Heiri Wandeler, Sven BacherAbstract:Wandeler, H., and Bacher, S. 2006. Insect-transmitted urediniospores of the rust Puccinia punctiformis cause systemic infections in established Cirsium arvense plants. Phytopathology 96:813-818. The rust fungus Puccinia punctiformis has potential as a biological control agent for creeping thistle Cirsium arvense, because systemically infected shoots usually die before flowering. The mechanism of rust transfer as well as the spore type responsible for systemic infections have been a source of controversy. One possibility of successful transmission is the use of the weevil Ceratapion onopordi as a vector. Our results from a garden experiment show that urediniospores transmitted by the weevil are able to induce systemic infections in established thistle clones. Furthermore, the weevil origin and the date of rust treatment significantly influenced the number of rust-infected shoots. The earlier a shoot was treated, the higher the probability of rust transmission. These results challenge the current belief that teliospores passing through the soil and infecting root buds are the major cause of systemic infections in the field. Further research on biological control of creeping thistle should therefore concentrate on the application of urediniospores to enhance systemic rust infections.
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mutualistic interaction between a weevil and a rust fungus two parasites of the weed Cirsium arvense
2001Co-Authors: Jurg Friedli, Sven BacherAbstract:We present a mutualism between a stem-boring weevil, Apion onopordi Kirby (Coleoptera: Apionidae), and a rust fungus, Puccinia punctiformis (Str.) Rohl. (Uredinales), both parasites of the creeping thistle, Cirsium arvense (L.) Scop. (Asteraceae). Females, but not males, of A. onopordi induced systemic rust infections of thistle shoots in the season after they were attacked by the weevil, indicating that insect oviposition is a crucial stage in pathogen transmission. Adult weevils emerged from systemically infected thistle shoots were heavier than weevils from healthy C. arvense shoots. Heavier females had a higher fecundity and laid larger eggs. The weevil preferred to deposit eggs in systemically rust-infected over healthy thistle shoots, which seemed to be a sub-optimal host. This is to our knowledge the first report of a mutualistic interaction between an herbivorous insect and a biotrophic plant pathogen. The mechanism responsible for the advantage of rust-infected shoots for A. onopordi causes a different outcome in other thistle herbivores, and therefore can not be explained by a general enhancement of nutritional quality in rust-infected tissue. This mutualism likely has evolved from a competitive relationship. Unlike other thistle herbivores A. onopordi seems to be better suited as mutualist for P. punctiformis because of its small impact on the host plant and its feeding niche on plant parts not directly associated with pathogen reproduction.
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effect of herbivore density timing of attack and plant community on performance of creeping thistle Cirsium arvense l scop asteraceae
2000Co-Authors: Sven Bacher, F SchwabAbstract:Creeping thistle, Cirsium arvense (L.) Scop. (Asteraceae), is one of the most serious weeds in ecological compensation areas (within-field or border refugia) in Europe. Since conventional weed control measures are restricted in compensation areas, augmenting indigenous agents for biological control of the weed may be a feasible alternative. In this paper, we studied the effect of density of the shield beetle, Cassida rubiginosa Muller (Coleoptera, Chrysomelidae), and two vegetation types typical for ecological compensation areas, on the performance of creeping thistle plants in an open field experiment. Early-season larval feeding had no measurable effect on creeping thistle growth, while late-season feeding significantly reduced shoot growth. These findings were attributed to higher feeding rates of the herbivores at higher ambient temperatures late in the season. Defoliation had a strong effect on the above-ground performance of C. arvense plants, but not on the below-ground performance. In contrast, th...
Antonio Evidente - One of the best experts on this subject based on the ideXlab platform.
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curvulin and phaeosphaeride a from paraphoma sp vizr 1 46 isolated from Cirsium arvense as potential herbicides
2018Co-Authors: Ekaterina V Poluektova, Antonio Evidente, Yuriy Tokarev, Sofia Sokornova, Leonid Chisty, Alexander BerestetskiyAbstract:Phoma-like fungi are known as producers of diverse spectrum of secondary metabolites, including phytotoxins. Our bioassays had shown that extracts of Paraphoma sp. VIZR 1.46, a pathogen of Cirsium arvense, are phytotoxic. In this study, two phytotoxically active metabolites were isolated from Paraphoma sp. VIZR 1.46 liquid and solid cultures and identified as curvulin and phaeosphaeride A, respectively. The latter is reported also for the first time as a fungal phytotoxic product with potential herbicidal activity. Both metabolites were assayed for phytotoxic, antimicrobial and zootoxic activities. Curvulin and phaeosphaeride A were tested on weedy and agrarian plants, fungi, Gram-positive and Gram-negative bacteria, and on paramecia. Curvulin was shown to be weakly phytotoxic, while phaeosphaeride A caused severe necrotic lesions on all the tested plants. To evaluate phaeosphaeride A’s herbicidal efficacy, the phytotoxic activity of this compound in combination with five different adjuvants was studied. Hasten at 0.1% (v/v) was found to be the most potent and compatible adjuvant, and its combination with 0.5% (v/v) semi-purified extract of Paraphoma sp. VIZR 1.46 solid culture exhibited maximum damage to C. arvense plants. These findings may offer significant importance for further investigation of herbicidal potential of phaeosphaeride A and possibly in devising new herbicide of natural origin.
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phomachalasins a d 26 oxa 16 and 15 cytochalasans produced by phoma exigua var exigua a potential mycoherbicide for Cirsium arvense biocontrol
2011Co-Authors: Antonio Evidente, Alexander Berestetskiy, Alessio Cimmino, Anna Andolfi, Andrea MottaAbstract:Phoma exigua var. exigua, a fungal pathogen isolated from Cirsium arvense and Sonchus arvensis, proposed as a biocontrol agent of this noxious perennial weeds, produces in liquid and solid cultures different phytotoxic metabolites with potential herbicidal activity. The phytotoxic cytochalasins B, F, Z2, and Z3 and deoxaphomin were previously identified together with p-hydroxybenzaldehyde. Using spectroscopic methods, four new cytochalasins, termed phomachalasins A–D, were isolated and characterized as three new closely related 26-oxa[16] and one new [15]cytochalasans. They belong to a new subgroup of cytochalasans bearing a 1,2,3,4,6,7-hexasubstituted bicycle[3.2.0]heptene joined to the macrocyclic ring. None of the four new metabolites showed phytotoxic or antimicrobial activity. The lack of both phytotoxic and antimicrobial activities showed by all phomachalasins A–D was probably due to the strong modification of both functionalities and conformational freedom of the macrocyclic ring caused by its junction with the bulky and quite rigid new bicycle, namely bicycle[3.2.0]heptene.
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stagonolides g i and modiolide a nonenolides produced by stagonospora cirsii a potential mycoherbicide for Cirsium arvense
2008Co-Authors: Antonio Evidente, Alexander Berestetskiy, Anna Andolfi, Alessio Cimmino, Andrea MottaAbstract:Stagonospora cirsii Davis, a fungal pathogen isolated from Cirsium arvense (commonly called Canada thistle) and proposed as a potential mycoherbicide of this perennial noxious weed, produces phytotoxic metabolites in liquid and solid cultures. Stagonolide, the main phytotoxic metabolite, and five new related nonenolides, named stagonolides B−F, were isolated from the fungus. When grown on solid culture, nonenolide yields increased. A further four nonenolides were isolated and characterized by spectroscopy. Three were new compounds and named stagonolides G−I, and the fourth was identified as modiolide A, previously isolated from Paraphaeosphaeria sp., a fungus separated from the horse mussel. Leaf disk-puncture assays at 1 mg/mL of stagonolides H−I and modiolide A were phytotoxic to C. arvense. Only stagonolide H inhibited chicory seedling root growth. The most potent toxin, stagonolide H, indicated selectivity when tested on leaves of eight different plants: Canada thistle was most sensitive to the compound.
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phyllostictines a d oxazatricycloalkenones produced by phyllosticta cirsii a potential mycoherbicide for Cirsium arvense biocontrol
2008Co-Authors: Antonio Evidente, Maria Chiara Zonno, Maurizio Vurro, Charles L Cantrell, Anna Andolfi, Alessio Cimmino, Andrea MottaAbstract:Abstract Phyllosticta cirsii , a fungal pathogen isolated from Cirsium arvense and proposed as biocontrol agent of this noxious perennial weed, produces in liquid cultures different phytotoxic metabolites with potential herbicidal activity. Four new oxazatricycloalkenones, named phyllostictines A–D, were isolated and characterized using essentially spectroscopic and chemical methods. Tested by leaf-puncture assay on the fungal host plant phyllostictine A proved to be highly toxic. The phytotoxicity decreases when both the dimension and the conformational freedom of the macrocyclic ring change, as in phyllostictines B and D, and it is totally lost when also the functionalization of the same ring is modified, as in phyllostictine C. Beside its phytotoxic properties, phyllostictine A has no antifungal activity, an interesting antibiotic activity only against Gram+ bacteria, and a noticeable zootoxic activity when tested at high concentrations. The integrity of the oxazatricycloalkenone system appears to be an important feature to preserve these activities.
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nonenolides and cytochalasins with phytotoxic activity against Cirsium arvense and sonchus arvensis a structure activity relationships study
2008Co-Authors: Alexander Berestetskiy, Anna Andolfi, Galina Mitina, A I Dmitriev, Iosif Lisker, Antonio EvidenteAbstract:Abstract A structure–activity relationships study was conducted assaying 15 natural analogues and derivatives belonging to two groups of organic compounds, nonenolides and cytochalasins, for their toxicity against the composite perennial weeds Cirsium arvense and Sonchus arvensis occurring through the temperate region of world. The toxic nonenolides (stagonolide, putaminoxin, pinolidoxin) and cytochalasins (deoxaphomin, cytochalasins A, B, F, T, Z2 and Z3) were isolated from phytopathogenic Stagonospora, Phoma and Ascochyta spp. The pinolidoxin (7,8-O,O′-diacetyl- and 7,8-O,O′-isopropylidene-pinolidoxin) and cytochalasins B (21,22-dihydro-, 7-O-acetyl- and 7,20-O,O′-diacetyl-cytochalasin B) derivatives were obtained by chemical modifications of the corresponding toxins. Among the 15 compounds tested, stagonolide and deoxaphomin proved to be the most phytotoxic to C. arvense and S. arvensis leaves, respectively. The tested phytotoxic nonenolides were stronger inhibitors of photosynthesis in C. arvense leaves than cytochalasines A and B. Stagonolide had less effect on membrane permeability in C. arvense leaves than cytochalasin B. Significant changes of light absorption by C. arvense leaves in visible and infrared spectra were caused by stagonolide. The functional groups and the conformational freedom of the ring, appear to be important structural features for the nonenolides toxicity, whereas and the presence of the hydroxy group at C-7, the functional group at C-20 and the conformational freedom of the macrocyclic ring are important for the cytochalasins toxicity.
Andrea Motta - One of the best experts on this subject based on the ideXlab platform.
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stagonolides g i and modiolide a nonenolides produced by stagonospora cirsii a potential mycoherbicide for Cirsium arvense
2008Co-Authors: Antonio Evidente, Alexander Berestetskiy, Anna Andolfi, Alessio Cimmino, Andrea MottaAbstract:Stagonospora cirsii Davis, a fungal pathogen isolated from Cirsium arvense (commonly called Canada thistle) and proposed as a potential mycoherbicide of this perennial noxious weed, produces phytotoxic metabolites in liquid and solid cultures. Stagonolide, the main phytotoxic metabolite, and five new related nonenolides, named stagonolides B−F, were isolated from the fungus. When grown on solid culture, nonenolide yields increased. A further four nonenolides were isolated and characterized by spectroscopy. Three were new compounds and named stagonolides G−I, and the fourth was identified as modiolide A, previously isolated from Paraphaeosphaeria sp., a fungus separated from the horse mussel. Leaf disk-puncture assays at 1 mg/mL of stagonolides H−I and modiolide A were phytotoxic to C. arvense. Only stagonolide H inhibited chicory seedling root growth. The most potent toxin, stagonolide H, indicated selectivity when tested on leaves of eight different plants: Canada thistle was most sensitive to the compound.
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phyllostictines a d oxazatricycloalkenones produced by phyllosticta cirsii a potential mycoherbicide for Cirsium arvense biocontrol
2008Co-Authors: Antonio Evidente, Maria Chiara Zonno, Maurizio Vurro, Charles L Cantrell, Anna Andolfi, Alessio Cimmino, Andrea MottaAbstract:Abstract Phyllosticta cirsii , a fungal pathogen isolated from Cirsium arvense and proposed as biocontrol agent of this noxious perennial weed, produces in liquid cultures different phytotoxic metabolites with potential herbicidal activity. Four new oxazatricycloalkenones, named phyllostictines A–D, were isolated and characterized using essentially spectroscopic and chemical methods. Tested by leaf-puncture assay on the fungal host plant phyllostictine A proved to be highly toxic. The phytotoxicity decreases when both the dimension and the conformational freedom of the macrocyclic ring change, as in phyllostictines B and D, and it is totally lost when also the functionalization of the same ring is modified, as in phyllostictine C. Beside its phytotoxic properties, phyllostictine A has no antifungal activity, an interesting antibiotic activity only against Gram+ bacteria, and a noticeable zootoxic activity when tested at high concentrations. The integrity of the oxazatricycloalkenone system appears to be an important feature to preserve these activities.
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phyllostoxin and phyllostin bioactive metabolites produced by phyllosticta cirsii a potential mycoherbicide for Cirsium arvense biocontrol
2008Co-Authors: Antonio Evidente, Maria Chiara Zonno, Maurizio Vurro, Anna Andolfi, Alessio Cimmino, Andrea MottaAbstract:Phyllosticta cirsii, a fungal pathogen isolated from diseased Cirsium arvense leaves and evaluated as a biocontrol agent of this noxious perennial weed, produces different phytotoxic metabolites with potential herbicidal activity when grown in liquid cultures. Phyllostictines A−D, four novel oxazatricycloalkenones, were recently isolated from this pathogen and chemically and biologically characterized. Further purification of the same organic extract provided two other metabolites, named phyllostoxin (1) and phyllostin (2), which were characterized by spectroscopic technique (essentially NMR and MS). Phyllostoxin and phyllostin proved to be a new pentasubstituted bicyclo-octatrienyl acetic acid ester and a new pentasubstituted hexahydrobenzodioxine carboxylic acid methyl ester, respectively. When tested on punctured C. arvense leaves, phyllostoxin proved to be highly phytotoxic, causing rapid and large necrosis, whereas phyllostin had no phytotoxicity in this bioassay. This is not surprising, considering ...
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stagonolides b f nonenolides produced by stagonospora cirsii a potential mycoherbicide of Cirsium arvense
2008Co-Authors: Antonio Evidente, Alexander Berestetskiy, Anna Andolfi, Alessio Cimmino, Galina Mitina, Andrea MottaAbstract:Stagonospora cirsii, a fungal pathogen isolated from Cirsium arvense and proposed as a potential mycoherbicide of this perennial noxious weed, produces phytotoxic metabolites in liquid and solid cultures. Recently, the main metabolite, stagonolide (1), with interesting phytotoxic properties, was isolated from a liquid culture and characterized as a new nonenolide. In the present work this same fungus, grown in solid culture, exhibited an increased capacity to produce nonenolides. Five new nonenolides, named stagonolides B−F (2–6), were isolated and characterized using spectroscopic methods. When tested by a leaf disk puncture assay at a concentration of 1 mg/mL, these compounds showed no toxicity to C. arvense and Sonchus arvensis, whereas stagonolide (1) was highly toxic. Stagonolide (1) and stagonolide C (3) were weakly toxic to Colpoda steinii, a protozoan, when tested at 0.05 mg/mL, with the other stagonolides nontoxic. A number of structure–activity relationship observations were made.
David P Horvath - One of the best experts on this subject based on the ideXlab platform.
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invasion history of north american canada thistle Cirsium arvense
2012Co-Authors: Alessia Guggisberg, David P Horvath, Michael E. Foley, Loren H Rieseberg, Erik Welk, R Sforza, James V AndersonAbstract:Aim Canada thistle (Cirsium arvense– Cardueae, Asteraceae) is one of the worst invasive plants world-wide. Native to Eurasia, its unintentional introduction into North America now threatens the native flora and is responsible for enormous agricultural losses. The goals of this study are to: (1) reconstruct the evolutionary history of C. arvense and estimate how often it may have colonized North America, (2) compare the genetic diversity between European and North American populations to detect signs of demographic bottlenecks and/or patterns of population admixture, and (3) conduct bioclimatic comparisons to infer eventual niche shifts following this species’ introduction into North America. Location Europe and North America. Methods A total of 1522 individuals from 58 populations were investigated with six microsatellite markers. Estimates of heterozygosity (HE) and allelic richness (RS) were quantified for each population, and population structure was inferred via analyses of molecular variance (AMOVAs), principal components analyses (PCAs), Mantel tests and Bayesian clustering analyses. Climatic niche spaces were based on 19 bioclimatic variables extracted from approximately 32,000 locations covering the entire range, and compared using PCA and hierarchical cluster analysis. Results Although there is evidence of multiple introductions from divergent European lineages, North American populations of C. arvense exhibited significantly lower levels of genetic diversity than their putative ancestors. Bioclimatic comparisons pointed to a high degree of niche conservatism during invasion, but indicated that genotypes from the former USSR and Central European mountain chains were probably best adapted to invade North America upon entry into the continent. Main conclusions Genetic and historical data suggest that C. arvense first entered North America from Western Europe with the first European settlers, and was later introduced from Eastern Europe into the prairie states during the agricultural boom. The species went through a significant bottleneck following its introduction into the New World, but the level of genetic diversity remained high owing to admixture between genetically differentiated lineages and to a highly efficient outcrossing breeding system.
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assessing genetic diversity of canada thistle Cirsium arvense in north america with microsatellites
2010Co-Authors: Tracey Bodo A Slotta, Michael E. Foley, Shaioman Chao, Ruth A Hufbauer, David P HorvathAbstract:Invasive species such as Canada thistle pose a significant threat to ecosystems. The risk of introducing invasive species has increased with human activities, and the effects of such events have economic and aesthetic impacts. Native to Europe, Canada thistle is now established throughout temperate North America. Although there is documentation of early occurrences to North America, little is known on how it has become established in diverse habitats or how it continues to spread. We examined genetic diversity within and among nearly 1,700 Canada thistle individuals from 85 North American locations with the use of seven microsatellite markers in order to address these questions. PAUP and STRUCTURE programs were used to assess genetic diversity and relationships within and between populations. Populations exhibited greater within-population diversity (. 60%) than expected for a reported clonally reproducing species. Total diversity of sampled locations in North America (0.183) was less than previously reported for European locations (0.715), but the greater mean difference between North American populations (0.264 relative to 0.246 from England) suggests strong founder effects or restriction of gene flow influencing individual populations. Furthermore, analyses identified numerous instances where individuals from geographically distant regions clustered together, indicating long-distance translocation of propogules. However, isolation by distance analysis showed significant correlation between location and population genetic distances (r 5 0.1917, P 5 0.006). Within populations, nearly 92% of individuals sampled harbored unique multilocus genotypes, strongly suggesting that sexual reproduction is common. Within populations, analysis of genetic structure indicated significant admixture of genotypes throughout the invasive range in North America. The recurrent distribution of seed throughout North America has led to a highly diverse gene pool and increased the adaptive success Canada thistle to a wide variety of habitats. Future technologies developed for control of Canada thistle should consider this diversity. Nomenclature: Canada thistle, Cirsium arvense (L.) Scop. CIRAR.
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development of polymorphic markers for Cirsium arvense canada thistle and their amplification in closely related taxa
2005Co-Authors: Tracey Bodo A Slotta, Michael E. Foley, David P HorvathAbstract:Suppression of invasive Canada thistle, Cirsium arvense, with biological control agents has stalled because introduced agents were not host-specific. To aid in the development of more effective management strategies, molecular markers are needed to examine the genetic structure of Canada thistle populations. Microsatellite (simple sequence repeat) markers were developed and intersimple sequence repeat (ISSR) markers were tested for North American populations. An average of nine polymorphic alleles per microsatellite locus and 11 per ISSR locus were detected. These will be used to examine the genetic structure of C. arvense in the northern Great Plains and their transferability to endemic Cirsium spp.