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Anne Grandmougin-ferjani - One of the best experts on this subject based on the ideXlab platform.
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Arbuscular mycorrhiza partially protect chicory roots against oxidative stress induced by two fungicides, Fenpropimorph and fenhexamid
Mycorrhiza, 2010Co-Authors: Estelle Campagnac, Djouher Debiane, Guillaume Garçon, Anthony Verdin, Joël Fontaine, Roger Durand, Pirouz Shirali, Anissa Lounès-hadj Sahraoui, Frédéric Laruelle, Anne Grandmougin-ferjaniAbstract:The present work examined the oxidative stress induced by different concentrations (0.02 and 0.2 mg l-1) of two sterol biosynthesis inhibitor fungicides (Fenpropimorph and fenhexamid) in non-target chicory root colonised or not by Glomus intraradices in a monoxenic system. The fungicides were found to cause oxidative damage by increasing lipid peroxidation measured by malondialdehyde production in non-colonised roots. Detoxification of the H_2O_2 product was measured at 0.2 mg l-1 of Fenpropimorph by an increase in peroxidase activities suggesting an antioxidant capacity in these roots. Moreover, this study pointed out the ability of arbuscular mycorrhiza to alleviate partially the oxidative stress in chicory roots, probably by lowering reactive oxygen species concentrations, resulting from increases in antioxidant defences. Our results suggest that the enhanced fungicide tolerance in the AM symbiosis could be related to less cell membrane damage.
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Fenpropimorph slows down the sterol pathway and the development of the arbuscular mycorrhizal fungus Glomus intraradices
Mycorrhiza, 2009Co-Authors: Estelle Campagnac, Anissa Lounès-hadj Sahraoui, Frédéric Laruelle, J. Fontaine, R. Durand, Anne Grandmougin-ferjaniAbstract:The direct impact of Fenpropimorph on the sterol biosynthesis pathway of Glomus intraradices when extraradical mycelia alone are in contact with the fungicide was investigated using monoxenic cultures. Bi-compartmental Petri plates allowed culture of mycorrhizal chicory roots in a compartment without Fenpropimorph and exposure of extraradical hyphae to the presence of increasing concentrations of Fenpropimorph (0, 0.02, 0.2, 2, 20 mg l^−1). In the fungal compartment, sporulation, hyphal growth, and fungal biomass were already reduced at the lowest fungicide concentration. A decrease in total sterols, in addition to an increase in the amount of squalene and no accumulation of abnormal sterols, suggests that the sterol pathway is severely slowed down or that squalene epoxidase was inhibited by Fenpropimorph in G. intraradices . In the root compartment, neither extraradical and intraradical development of the arbuscular mycorrhizal (AM) fungus nor root growth was affected when they were not in direct contact with the fungicide; only hyphal length was significantly affected at 2 mg l^−1 of Fenpropimorph. Our results clearly demonstrate a direct impact of Fenpropimorph on the AM fungus by a perturbation of its sterol metabolism.
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Differential effects of Fenpropimorph and fenhexamid, two sterol biosynthesis inhibitor fungicides, on arbuscular mycorrhizal development and sterol metabolism in carrot roots.
Phytochemistry, 2008Co-Authors: Estelle Campagnac, Joël Fontaine, Roger Durand, Frédéric Laruelle, Anissa Lounès-hadj Sahraoui, Anne Grandmougin-ferjaniAbstract:Abstract Sterols composition of transformed carrot roots incubated in presence of increasing concentrations of Fenpropimorph (0.02; 0.2; 2 mg l−1) and fenhexamid (0.02; 0.2; 2; 20 mg l−1), colonized or not by Glomus intraradices was determined. In mycorrhizal roots treated with Fenpropimorph, normal Δ5-sterols were replaced by unusual compounds such as 9β,19-cyclopropylsterols (24-methylpollinastanol), Δ8,14-sterols (ergosta-8,14-dienol, stigmasta-8,14-dienol), Δ8-sterols (Δ8 sitosterol) and Δ7-sterols (ergosta-7,22-dienol). After application of Fenpropimorph, a drastic reduction of the mycorrhizal root growth, root colonization and extraradical fungal development was observed. Application of fenhexamid did not modify sterol profiles and the total colonization of roots. But the arbuscule frequency of the fungal partner was significantly affected. Comparison of the effects caused by the tested fungicides indicates that the usual phytosterols may be involved in symbiosis development. Indeed, observed modifications of root sterols composition could explain the high Fenpropimorph toxicity to the AM symbiosis. However, the absence of sterolic modifications in the roots treated with fenhexamid could account for its more limited impact on mycorrhization.
Steven L. Kelly - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the role of sterol Δ8 → 7-isomerase in the sensitivity of Saccharomyces cerevisiae to Fenpropimorph
FEMS microbiology letters, 1994Co-Authors: Diane E. Kelly, Malcolm E. Rose, Steven L. KellyAbstract:Treatment of Saccharomyces cerevisiae with the morpholine fungicide Fenpropimorph was examined using both a wild-type and a mutant strain (erg2) defective in sterol delta 8-->7-isomerase. No resistance to Fenpropimorph was observed in the mutant strain after 3 days, although after 7 days the mutant and the wild-type strains had grown in concentrations of Fenpropimorph close to the saturating dose. Re-inoculation of both strains into fresh medium containing Fenpropimorph resulted in continued growth and this adaptation to fungicide tolerance was lost on subculture in the absence of Fenpropimorph. Analysis of the sterols present in the cells indicated that Fenpropimorph treatment resulted in the accumulation of delta 8,14-sterols. This accumulation and the corresponding depletion of ergosterol were correlated with growth inhibition rather than the presence of delta 8-sterols. Together with an absence of gene dosage effect for ERG2 on Fenpropimorph sensitivity, this supports the hypothesis that sterol delta 8-->7-isomerase inhibition does not contribute to the fungicidal activity of Fenpropimorph.
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investigation of the role of sterol δ8 7 isomerase in the sensitivity of saccharomyces cerevisiae to Fenpropimorph
Fems Microbiology Letters, 1994Co-Authors: Diane E. Kelly, Malcolm E. Rose, Steven L. KellyAbstract:Treatment of Saccharomyces cerevisiae with the morpholine fungicide Fenpropimorph was examined using both a wild-type and a mutant strain (erg2) defective in sterol delta 8-->7-isomerase. No resistance to Fenpropimorph was observed in the mutant strain after 3 days, although after 7 days the mutant and the wild-type strains had grown in concentrations of Fenpropimorph close to the saturating dose. Re-inoculation of both strains into fresh medium containing Fenpropimorph resulted in continued growth and this adaptation to fungicide tolerance was lost on subculture in the absence of Fenpropimorph. Analysis of the sterols present in the cells indicated that Fenpropimorph treatment resulted in the accumulation of delta 8,14-sterols. This accumulation and the corresponding depletion of ergosterol were correlated with growth inhibition rather than the presence of delta 8-sterols. Together with an absence of gene dosage effect for ERG2 on Fenpropimorph sensitivity, this supports the hypothesis that sterol delta 8-->7-isomerase inhibition does not contribute to the fungicidal activity of Fenpropimorph.
Pieter Spanoghe - One of the best experts on this subject based on the ideXlab platform.
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Formulation approaches to reduce post-application pesticide volatilisation from glass surfaces
The Science of the total environment, 2018Co-Authors: Michael Houbraken, David Senaeve, Edelbis López Dávila, Valens Habimana, Benny De Cauwer, Pieter SpanogheAbstract:Volatilisation is one of the main pathways for pesticide emission to the atmosphere. While formulation strategies and adjuvants are known to affect the fate of active ingredient, no general volatilisation reducing guidelines exist for formulation purposes. Moreover, as limited information on formulation effects is available, current pesticide fate models lack parameters characterising reduction of active ingredient volatilisation. The objective of this study was to investigate the volatilisation reducing potential of formulation types and adjuvants, and to propose an effective vapour pressure for pesticide fate modelling. Several formulations of Fenpropimorph, pyrimethanil and tebuconazole were produced and tested in a wind tunnel to evaluate the effect of formulation on active ingredient volatilisation. Produced emulsifiable concentrates with high volatile solvents did not offer any reduction in volatilisation, while the low volatile solvent reduced the volatilisation of pyrimethanil and Fenpropimorph with 79.2 and 52.9%, respectively. The microemulsion reduced the volatilisation of Fenpropimorph, pyrimethanil and tebuconazole with 57.6, 57.8 and 49.8%, respectively. High surfactant-active ingredient ratios (100:1) reduced the volatilisation of applied amount of pyrimethanil with 50%, on average. The effective vapour pressure of pyrimethanil formulated as a commercial available suspension concentrate was reduced by 33.8%. The commercial available emulsifiable concentrate did not reduce volatilisation of Fenpropimorph. Effective vapour pressures of formulated Fenpropimorph and pyrimethanil were determined and showed a high correlation with the amount volatilised within 48h. The saturated vapour pressure is useful when comparing the volatility of active ingredients, but effective vapour pressures are more appropriate to be used in pesticide fate models.
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Reduction of post-application pesticide volatilisation by adjuvants from glass surfaces
2016Co-Authors: Michael Houbraken, Pieter SpanogheAbstract:Agricultural use of pesticides has become a part of modern agriculture which contributes to the productivity and quality of the cultivated crop. Pesticides entering the environment through spray drift or run-off is the focus of several research areas. However, volatilisation of pesticides with a high vapour pressure can account for up to 80% of the total applied amount and can effect nearby crops, bystanders and residents. In this study, the effectiveness of adjuvants to reduce the volatilisation was researched. Dissipation of Fenpropimorph, pyrimethanil, tebuconazole and 2,4-D as pure active ingredient, formulated by different types of adjuvants and in commercial formulations was studied. An empirical model assuming exponential decay of the volatilisation rate was used to calculate the volatilisation. In 48 hours, up to 92% of the pure Fenpropimorph and 84% of the pure pyrimethanil was volatilised. Volatilisation of pesticides was reduced by the formulation. The commercial formulation of pyrimethanil and 2,4-D was able to reduce the volatilisation of both actives. On the other hand the formulation of Fenpropimorph or tebuconazole had little effect on volatilisation.
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influence of adjuvants on the dissipation of Fenpropimorph pyrimethanil chlorpyrifos and lindane on the solid gas interface
Chemosphere, 2015Co-Authors: Michael Houbraken, David Senaeve, Davina Fevery, Pieter SpanogheAbstract:The use of pesticides is an integral part of modern agriculture and contributes to the productivity and the quality of the cultivated crop. However, use of pesticides imposes a huge burden on the environment. Volatilisation of pesticides contaminates the environment, affects nearby crops, bystanders and residents but research to mitigate this environmental contamination remains scarce. In this study, the use of adjuvants to reduce the volatilisation and mitigate the environmental contamination was investigated. Dissipation of Fenpropimorph, pyrimethanil, chlorpyrifos-ethyl and lindane as pure active ingredient, formulated by different adjuvants and in a commercial formulation were studied. An empirical model assuming exponential decay of the volatilisation rate was used to calculate the volatilisation. In 48 h, up to 90% of the pure Fenpropimorph and lindane volatilised. Addition of adjuvants was shown to reduce the volatilisation of pesticides by up to 80%. Commercial formulation was able to reduce the volatilisation of pyrimethanil but the formulation of Fenpropimorph had no effect on its volatilisation.
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Influence of adjuvants on the dissipation of Fenpropimorph, pyrimethanil, chlorpyrifos and lindane on the solid/gas interface
Chemosphere, 2015Co-Authors: Michael Houbraken, David Senaeve, Davina Fevery, Pieter SpanogheAbstract:Abstract The use of pesticides is an integral part of modern agriculture and contributes to the productivity and the quality of the cultivated crop. However, use of pesticides imposes a huge burden on the environment. Volatilisation of pesticides contaminates the environment, affects nearby crops, bystanders and residents but research to mitigate this environmental contamination remains scarce. In this study, the use of adjuvants to reduce the volatilisation and mitigate the environmental contamination was investigated. Dissipation of Fenpropimorph, pyrimethanil, chlorpyrifos-ethyl and lindane as pure active ingredient, formulated by different adjuvants and in a commercial formulation were studied. An empirical model assuming exponential decay of the volatilisation rate was used to calculate the volatilisation. In 48 h, up to 90% of the pure Fenpropimorph and lindane volatilised. Addition of adjuvants was shown to reduce the volatilisation of pesticides by up to 80%. Commercial formulation was able to reduce the volatilisation of pyrimethanil but the formulation of Fenpropimorph had no effect on its volatilisation.
Pierre Leroux - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms of Resistance to Fenpropimorph and Terbinafine, Two Sterol Biosynthesis Inhibitors, in Nectria haematococca, a Phytopathogenic Fungus
Pesticide Biochemistry and Physiology, 1999Co-Authors: Alexandrine Lasseron-de Falandre, Danièle Debieu, Jocelyne Bach, Christian Malosse, Pierre LerouxAbstract:Abstract The mechanisms of resistance to terbinafine, a squalene epoxidase inhibitor, and to Fenpropimorph, a sterol Δ 14 -reductase and/or Δ 8 → Δ 7 -isomerase inhibitor, were investigated in laboratory mutants of the phytopathogenic fungus Nectria haematococca . Neither modified fungicide uptake nor fungicide metabolism could explain resistance in the mutants studied. The terbinafine-resistant mutants contained at least 10 times more squalene than the wild-type strain, and when cultivated in presence of terbinafine, they required a 30-times higher fungicide concentration to obtain a very high level of accumulated squalene similar to that of the wild-type strain. Thus, a reduced affinity of the squalene epoxidase toward both the substrate and the fungicide could explain terbinafine resistance in these mutants. In some Fenpropimorph-resistant mutants, the effects of Fenpropimorph on sterol biosynthesis were similar to those in the wild-type strain, suggesting that resistance could be due to tolerance to sterol Δ 8,14 -sterol accumulation and to Δ 5,7 -sterol decrease. In one of them, the major sterol in absence of fungicide was not ergosterol, but ergosta-5,7,22,24(24 1 )-tetraenol, indicating reduced Δ 24 (24 1 )-reductase activity. The potential role of a modified Δ 24 (24 1 ) reductase in Fenpropimorph resistance has yet to be elucidated. In the remaining Fenpropimorph-resistant mutants, much higher Fenpropimorph concentrations were required to cause ergosterol decreases similar to that in the wild-type strain, suggesting a Δ 14 -reductase modification. Among them, some mutants accumulated Δ 8 -sterols as well as Δ 8,14 -sterols, indicating that the mechanism of resistance may be due to reduced affinity of the Δ 14 -reductase toward Fenpropimorph, whereas the other mutants accumulated only Δ 8,14 -sterols. Those last mutants contained much larger amounts of 4,4-dimethyl and 4α-methyl sterols than the wild-type strain, in the absence of fungicide. The most abundant methylated sterol was 4,4-dimethylfecosterol, the presumed product of the Δ 14 -reductase, suggesting that resistance may be due to overproduction of the Δ 14 -reductase in these mutants.
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Ergosterol biosynthesis and its inhibition by Fenpropimorph in Fusarium species
Phytochemistry, 1992Co-Authors: Danièle Debieu, Claude Gall, Michel Gredt, Jocelyne Bach, Christian Malosse, Pierre LerouxAbstract:Abstract In the mycelium of all the Fusarium species studied, the major sterol was ergosterol in the absence of Fenpropimorph. In the presence of this fungicide Fenpropimorph-sensitive strains, with the exception of F. nivale , accumulated mainly Δ 8,14 -sterols and tolerant ones accumulated either both Δ 8,14 - and Δ 8 -sterols or only Δ 8 -sterols. This seemed to indicate that Fenpropimorph toxicity was related to sterol Δ 14 -reductase sensitivity. In F. nivale , which was highly sensitive to Fenpropimorph, the accumulation of only Δ 8 -sterols indicated that the main target enzyme was sterol Δ 8 →Δ 7 -isomerase. In addition to Δ 8,14 -and Δ 8 -sterols, squalene was accumulated in very high amounts in several strains; the level of squalene accumulation did not seem to be correlated with Fenpropimorph sensitivity.
Estelle Campagnac - One of the best experts on this subject based on the ideXlab platform.
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Arbuscular mycorrhiza partially protect chicory roots against oxidative stress induced by two fungicides, Fenpropimorph and fenhexamid
Mycorrhiza, 2010Co-Authors: Estelle Campagnac, Djouher Debiane, Guillaume Garçon, Anthony Verdin, Joël Fontaine, Roger Durand, Pirouz Shirali, Anissa Lounès-hadj Sahraoui, Frédéric Laruelle, Anne Grandmougin-ferjaniAbstract:The present work examined the oxidative stress induced by different concentrations (0.02 and 0.2 mg l-1) of two sterol biosynthesis inhibitor fungicides (Fenpropimorph and fenhexamid) in non-target chicory root colonised or not by Glomus intraradices in a monoxenic system. The fungicides were found to cause oxidative damage by increasing lipid peroxidation measured by malondialdehyde production in non-colonised roots. Detoxification of the H_2O_2 product was measured at 0.2 mg l-1 of Fenpropimorph by an increase in peroxidase activities suggesting an antioxidant capacity in these roots. Moreover, this study pointed out the ability of arbuscular mycorrhiza to alleviate partially the oxidative stress in chicory roots, probably by lowering reactive oxygen species concentrations, resulting from increases in antioxidant defences. Our results suggest that the enhanced fungicide tolerance in the AM symbiosis could be related to less cell membrane damage.
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Fenpropimorph slows down the sterol pathway and the development of the arbuscular mycorrhizal fungus Glomus intraradices
Mycorrhiza, 2009Co-Authors: Estelle Campagnac, Anissa Lounès-hadj Sahraoui, Frédéric Laruelle, J. Fontaine, R. Durand, Anne Grandmougin-ferjaniAbstract:The direct impact of Fenpropimorph on the sterol biosynthesis pathway of Glomus intraradices when extraradical mycelia alone are in contact with the fungicide was investigated using monoxenic cultures. Bi-compartmental Petri plates allowed culture of mycorrhizal chicory roots in a compartment without Fenpropimorph and exposure of extraradical hyphae to the presence of increasing concentrations of Fenpropimorph (0, 0.02, 0.2, 2, 20 mg l^−1). In the fungal compartment, sporulation, hyphal growth, and fungal biomass were already reduced at the lowest fungicide concentration. A decrease in total sterols, in addition to an increase in the amount of squalene and no accumulation of abnormal sterols, suggests that the sterol pathway is severely slowed down or that squalene epoxidase was inhibited by Fenpropimorph in G. intraradices . In the root compartment, neither extraradical and intraradical development of the arbuscular mycorrhizal (AM) fungus nor root growth was affected when they were not in direct contact with the fungicide; only hyphal length was significantly affected at 2 mg l^−1 of Fenpropimorph. Our results clearly demonstrate a direct impact of Fenpropimorph on the AM fungus by a perturbation of its sterol metabolism.
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Differential effects of Fenpropimorph and fenhexamid, two sterol biosynthesis inhibitor fungicides, on arbuscular mycorrhizal development and sterol metabolism in carrot roots.
Phytochemistry, 2008Co-Authors: Estelle Campagnac, Joël Fontaine, Roger Durand, Frédéric Laruelle, Anissa Lounès-hadj Sahraoui, Anne Grandmougin-ferjaniAbstract:Abstract Sterols composition of transformed carrot roots incubated in presence of increasing concentrations of Fenpropimorph (0.02; 0.2; 2 mg l−1) and fenhexamid (0.02; 0.2; 2; 20 mg l−1), colonized or not by Glomus intraradices was determined. In mycorrhizal roots treated with Fenpropimorph, normal Δ5-sterols were replaced by unusual compounds such as 9β,19-cyclopropylsterols (24-methylpollinastanol), Δ8,14-sterols (ergosta-8,14-dienol, stigmasta-8,14-dienol), Δ8-sterols (Δ8 sitosterol) and Δ7-sterols (ergosta-7,22-dienol). After application of Fenpropimorph, a drastic reduction of the mycorrhizal root growth, root colonization and extraradical fungal development was observed. Application of fenhexamid did not modify sterol profiles and the total colonization of roots. But the arbuscule frequency of the fungal partner was significantly affected. Comparison of the effects caused by the tested fungicides indicates that the usual phytosterols may be involved in symbiosis development. Indeed, observed modifications of root sterols composition could explain the high Fenpropimorph toxicity to the AM symbiosis. However, the absence of sterolic modifications in the roots treated with fenhexamid could account for its more limited impact on mycorrhization.