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G. Défago - One of the best experts on this subject based on the ideXlab platform.
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issr fingerprinting for the assessment of the Bindweed biocontrol agent stagonospora convolvuli la39 after field release
Letters in Applied Microbiology, 2007Co-Authors: Désirée Boss, G. Défago, Monika Maurhofer, Marcello Zala, Patrick C BrunnerAbstract:Aims: To develop a molecular identification method based on ISSR fingerprints to monitor the fungal leaf pathogen Stagonospora convolvuli LA39 used to biologically control Bindweeds after a field release. Methods and results: The developed method proved to be suitable to clearly distinguish LA39 from resident Stagonospora spp. and was applied in two field experiments. First, the environmental persistence of LA39 was assessed in an overwintering experiment. LA39 could be re-isolated from infected Bindweed 1 year after field application, but with very low frequency of occurrence. Secondly, LA39 was applied in an area with natural Bindweed infestation and re-isolated from infected Bindweed. The dispersal of LA39 during one season was poor (4–5 m). Conclusions: ISSR fingerprinting has been shown to be a valuable tool to monitor the environmental fate of S. convolvuli in the field. It is concluded that an LA39-based mycoherbicide will have minimal environmental impact caused by the restricted mobility, poor proliferation and poor persistence over seasons of LA39. Significance and impact of the study: Studies about the dispersal and survival of biocontrol agents after field release as well as the development of methods needed for this purpose are indispensable for a comprehensive risk assessment for biocontrol agents.
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elsinochrome a production by the Bindweed biocontrol fungus stagonospora convolvuli la39 does not pose a risk to the environment or the consumer of treated crops
FEMS Microbiology Ecology, 2007Co-Authors: Désirée Boss, Monika Maurhofer, Elsbeth Schlapfer, G. DéfagoAbstract:Biological control as an alternative to chemical pesticides is of increasing public interest. However, to ensure safe use of biocontrol methods, strategies to assess the possible risks need to be developed. The production of toxic metabolites is an aspect which has so far largely been neglected in the risk assessment and the registration process for biocontrol products. We have evaluated the risks of elsinochrome A (ELA) and leptosphaerodione production by the fungus Stagonospora convolvuli LA39, an effective biocontrol agent used against Bindweeds. The toxicity of the two metabolites to bacteria, protozoa, fungi and plants was evaluated in in vitro assays. The most sensitive bacteria and fungi were already affected at 0.01–0.07 μM ELA, whereas plants were far less sensitive. Leptosphaerodione was less toxic than ELA. Subsequently, it was investigated whether ELA is present in the applied biocontrol product or LA39-treated Bindweed and crop plants. In plants ELA was never detected and in the biocontrol product the ELA concentration was far too low to have toxic effects even on the most sensitive organisms. We conclude that the production of ELA by biocontrol strain LA39 does not pose a risk to the environment or to the consumer.
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Relationship between aggressiveness of Stagonospora sp. isolates on field and hedge Bindweeds, and in vitro production of fungal metabolites cercosporin, elsinochrome A and leptosphaerodione
European Journal of Plant Pathology, 2005Co-Authors: Monday O. Ahonsi, Monika Maurhofer, Désirée Boss, G. DéfagoAbstract:Stagonospora convolvuli LA39, an effective biocontrol agent of Convolvulus arvensis (field Bindweed) and Calystegia sepium (hedge Bindweed) produces phytotoxic metabolites leptosphaerodione and elsinochrome A. Stagonospora isolate 214Caa produces the toxin cercosporin. If toxic metabolite production is not linked to the pathogenic ability of the fungus on Bindweeds, selection of aggressive strains with limited or no production of the metabolites would reduce any perceived risk of using strains of the fungus as a mycoherbicide. Therefore, 30 isolates of Stagonospora sp. including LA39 and 214Caa were characterised for aggressiveness on both Bindweeds, and production of the three metabolites. Nine isolates were more aggressive than LA39 on both Bindweeds. Classification of isolates based on metabolite type agreed largely with previous similar characterisation based on polymerase chain reaction-restriction fragment length polymorphism of internal transcribed spacer of ribosomal DNA. Cercosporin producers produced neither leptosphaerodione nor elsinochrome A and together with isolates that produce none of the three metabolites, were less pathogenic on Bindweeds. Conversely, there was a positive correlation between elsinochrome A and leptosphaerodione production, and each was positively correlated with aggressiveness of isolates on both Bindweeds. Generally, any isolate where elsinochrome A was not detected was not aggressive on any of the two Bindweeds. This probably implies that selecting elsinochrome A-negative, but aggressive Stagonospora strain(s) may be difficult. However, aggressive isolates may not produce elsinochrome A in planta at levels that could constitute any risk in the environment. In a preliminary attempt to determine the levels of elsinochrome A and leptosphaerodione produced in diseased Bindweeds, none of the toxins was detected in Stagonospora infected Bindweed leaves. Detailed investigation focusing on the detection and quantification of in planta production of elsinochrome A by Stagonospora isolates, and determination of the fate of elsinochrome A in the environment, and its relationship with leptosphaerodione may be essential. Similarly, development of molecular tools to monitor the mycoherbicide following field application is vital.
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Towards the biocontrol of Bindweeds with a mycoherbicide
BioControl, 2001Co-Authors: G. Défago, Hans-ulrich Ammon, Daniel Guntli, L. Cagán, B. Draeger, M.p. Greaves, D. Hoeke, L. Klimes, J. Lawrie, Y. Moënne-loccozAbstract:Within the framework of the European COST Action 816, afive-year collaboration between scientists from five Europeancountries has made an important contribution to biologicalcontrol of field and hedge Bindweeds ( Convolvulus arvensis and Calystegia sepium , respectively). A fungus Stagonosporaconvolvuli strain LA39, able to infect both field and hedgeBindweed, was found in the UK and its biocontrol efficacyimproved by optimising mass production, formulation and storagetechniques. This fungus controlled Bindweeds in both a cemeteryand in maize crops. Its use fits best in an integrated pestmanagement system where a green cover controls most of the weedsexcept the Bindweeds. DNA marker analyses indicate that thefungus reproduces sexually, which could be used to furtherimprove this mycoherbicide. In addition, the insect Melanagromyzaalbocilia , which itself exhibits biocontrol potential againstBindweeds, may be used in combination with LA39 to improve theability of the fungus to penetrate the stem of Bindweeds.Overall, the results suggest that S. convolvuli LA39 haspromising potential as a bioherbicide for control of field andhedge Bindweed.
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© 2001 Kluwer Academic Publishers. Printed in the Netherlands. Towards the biocontrol of Bindweeds with a mycoherbicide
2000Co-Authors: G. Défago, Hans-ulrich Ammon, Daniel Guntli, L. Cagán, B. Draeger, M.p. Greaves, D. Hoeke, L. Klimes, J. Lawrie, Y. Moënne-loccozAbstract:Abstract. Within the framework of the European COST Action 816, a five-year collabora-tion between scientists from five European countries has made an important contribution to biological control of field and hedge Bindweeds (Convolvulus arvensis and Calystegia sepium, respectively). A fungus Stagonospora convolvuli strain LA39, able to infect both field and hedge Bindweed, was found in the UK and its biocontrol efficacy improved by optimising mass production, formulation and storage techniques. This fungus controlled Bindweeds in both a cemetery and in maize crops. Its use fits best in an integrated pest management system where a green cover controls most of the weeds except the Bindweeds. DNA marker analyses indicate that the fungus reproduces sexually, which could be used to further improve this mycoherbicide. In addition, the insect Melanagromyza albocilia, which itself exhibits biocon-trol potential against Bindweeds, may be used in combination with LA39 to improve the ability of the fungus to penetrate the stem of Bindweeds. Overall, the results suggest that S. convolvul
Geert Baggerman - One of the best experts on this subject based on the ideXlab platform.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic β amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert BaggermanAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic beta amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert Baggerman, Annick Barre, Pierre Rouge, Willy J PeumansAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
E J Van Damme - One of the best experts on this subject based on the ideXlab platform.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic β amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert BaggermanAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic beta amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert Baggerman, Annick Barre, Pierre Rouge, Willy J PeumansAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
Willy J Peumans - One of the best experts on this subject based on the ideXlab platform.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic beta amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert Baggerman, Annick Barre, Pierre Rouge, Willy J PeumansAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
Bettina Hause - One of the best experts on this subject based on the ideXlab platform.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic β amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert BaggermanAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
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purification characterization immunolocalization and structural analysis of the abundant cytoplasmic beta amylase from calystegia sepium hedge Bindweed rhizomes
FEBS Journal, 2001Co-Authors: E J Van Damme, Bettina Hause, Geert Baggerman, Annick Barre, Pierre Rouge, Willy J PeumansAbstract:An abundant catalytically active β-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge Bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β-amylase is exclusively located in the cytoplasm. It is suggested that the hedge Bindweed rhizome β-amylase is a cytoplasmic vegetative storage protein.
