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Christophe Delye - One of the best experts on this subject based on the ideXlab platform.

  • ALOMYbase, a resource to investigate non-target-site-based resistance to herbicides inhibiting acetolactate-synthase (ALS) in the major grass weed Alopecurus myosuroides (black-grass)
    BMC genomics, 2015
    Co-Authors: Jérôme Gouzy, Jeanne Gardin, Sébastien Carrère, Christophe Delye
    Abstract:

    Background Herbicide resistance in agrestal weeds is a global problem threatening food security. Non-target-site resistance (NTSR) endowed by mechanisms neutralising the herbicide or compensating for its action is considered the most agronomically noxious type of resistance. Contrary to target-site resistance, NTSR mechanisms are far from being fully elucidated. A part of weed response to herbicide stress, NTSR is considered to be largely driven by gene regulation. Our purpose was to establish a transcriptome resource allowing investigation of the transcriptomic bases of NTSR in the major grass weed Alopecurus myosuroides L. (Poaceae) for which almost no genomic or transcriptomic data was available.

  • DNA Analysis of Herbarium Specimens of the Grass Weed Alopecurus myosuroides Reveals Herbicide Resistance Pre-Dated Herbicides
    PLoS ONE, 2013
    Co-Authors: Christophe Delye, Chrystel Deulvot, Bruno Chauvel
    Abstract:

    Acetyl-CoA carboxylase (ACCase) alleles carrying one point mutation that confers resistance to herbicides have been identified in arable grass weed populations where resistance has evolved under the selective pressure of herbicides. In an effort to determine whether herbicide resistance evolves from newly arisen mutations or from standing genetic variation in weed populations, we used herbarium specimens of the grass weed Alopecurus myosuroides to seek mutant ACCase alleles carrying an isoleucine-to-leucine substitution at codon 1781 that endows herbicide resistance. These specimens had been collected between 1788 and 1975, i.e., prior to the commercial release of herbicides inhibiting ACCase. Among the 734 specimens investigated, 685 yielded DNA suitable for PCR. Genotyping the ACCase locus using the derived Cleaved Amplified Polymorphic Sequence (dCAPS) technique identified one heterozygous mutant specimen that had been collected in 1888. Occurrence of a mutant codon encoding a leucine residue at codon 1781 at the heterozygous state was confirmed in this specimen by sequencing, clearly demonstrating that resistance to herbicides can pre-date herbicides in weeds. We conclude that point mutations endowing resistance to herbicides without having associated deleterious pleiotropic effects can be present in weed populations as part of their standing genetic variation, in frequencies higher than the mutation frequency, thereby facilitating their subsequent selection by herbicide applications.

  • non target site based resistance should be the centre of attention for herbicide resistance research Alopecurus myosuroides as an illustration
    Weed Research, 2011
    Co-Authors: Christophe Delye, Bruno Chauvel, Jeanne Gardin, Karelle Boucansaud, Cecile Petit
    Abstract:

    Delye C, Gardin JAC, Boucansaud K, Chauvel B & Petit C (2011). Non-target-site-based resistance should be the centre of attention for herbicide resistance research: Alopecurus myosuroides as an illustration. Weed Research51, 433–437. Summary Non-target-site-based resistance (NTSR) mechanisms can confer unpredictable resistance to herbicides with different chemistries or modes of action. In two French fields, 18% and 40% individual plants of Alopecurus myosuroides (black-grass), respectively, were resistant via NTSR to all the most effective herbicides approved for A. myosuroides control in wheat (fenoxaprop, clodinafop, pinoxaden, iodosulfuron+mesosulfuron and pyroxsulam) and to the broad-leaf-selective herbicide quizalofop. Pinoxaden and pyroxsulam had never been applied to these populations. In the absence of new herbicide modes of action, this renders a purely chemical control of A. myosuroides in winter cereals much more complex in these fields. A segregation analysis showed that multi-resistant phenotypes were endowed by multiple NTSR genes, underlining the complexity of NTSR. Yet, despite the threat posed to weed control, our lack of knowledge on NTSR is obvious. NTSR should therefore become the priority in herbicide resistance research.

  • geographical variation in resistance to acetyl coenzyme a carboxylase inhibiting herbicides across the range of the arable weed Alopecurus myosuroides black grass
    New Phytologist, 2010
    Co-Authors: Christophe Delye, Bruno Chauvel, Jean-philippe Guillemin, Séverine Michel, Aurelie Berard, Dominique Brunel, Fabrice Dessaint, Valerie Le Corre
    Abstract:

    Summary • The geographical structure of resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACCase) was investigated in the weed Alopecurus myosuroides (black-grass) across its geographical range to gain insight into the process of plant adaptation in response to anthropogenic selective pressures occurring in agricultural ecosystems. • We analysed 297 populations distributed across six countries in A. myosuroides’ main area of occupancy. The frequencies of plants resistant to two broadly used ACCase inhibitors and of seven mutant, resistant ACCase alleles were assessed using bioassays and genotyping, respectively. • Most of the resistance was not endowed by mutant ACCase alleles. Resistance and ACCase allele distribution patterns were characterized by mosaicism. The prevalence of resistance and of ACCase alleles differed among countries. • Resistance clearly evolved by redundant evolution of a set of resistance alleles or genes, most of which remain unidentified. Resistance in A. myosuroides was shaped by variation in the herbicide selective pressure at both the individual field level and the national level.

  • A molecular assay for the proactive detection of target site-based resistance to herbicides inhibiting acetolactate synthase in Alopecurus myosuroides
    Weed Research, 2008
    Co-Authors: Christophe Delye, Karelle Boucansaud
    Abstract:

    Summary Acetolactate synthase (ALS) inhibitors are the most resistance-prone herbicide group. Rapid resistance diagnosis is thus of importance for their optimal use. We formulate rules to use the derived cleaved amplified polymorphic sequence method to develop molecular tools detecting a change at a given codon, the nature of which is unknown. We applied them to Alopecurus myosuroides (black grass) to develop assays targeting ALS codons A122, P197, A205, W574 and S653 that are crucial for herbicide sensitivity. These assays detected W574L or P197T, or both substitutions, in most plants analysed from a field where ALS inhibitors failed after 3 years of use. Similar assays can easily be set up for any species. Given the rapidity of selection for resistance to ALS inhibitors, these assays should be very useful in proactive herbicide resistance diagnosis.

S. R. Moss - One of the best experts on this subject based on the ideXlab platform.

  • resistance profile of herbicide resistant Alopecurus myosuroides black grass populations in denmark
    Crop Protection, 2015
    Co-Authors: Eshagh Keshtkar, S. R. Moss, Solvejg K. Mathiassen, Per Kudsk
    Abstract:

    Alopecurus myosuroides Huds is one of the most important grass-weeds in North-western Europe and is also the most important herbicide-resistant weed species in European agricultural systems. Fifty-three Danish A. myosuroides populations, previously confirmed to be fenoxaprop-P resistant, were evaluated for five and two known mutation points within the ACCase and ALS genes, respectively. The resistance pattern of 28 out of the 53 populations was investigated to four herbicides using a seed bioassay technique. A whole plant dose response experiment was conducted on seven populations in 2012 and 2013 to evaluate the accuracy of the seed bioassay results. Two resistant populations from the UK and a susceptible population from Denmark were included as reference populations in all experiments. Of the 53 populations, nine (17%) populations were ACCase target site resistant (TSR), all with a mutation at the Ile-1781 position. No mutations conferring TSR to ALS inhibitors were detected in the 53 populations. The seed bioassay results showed that all populations had varying degrees of resistance to fenoxaprop-P. In contrast, all populations were susceptible to cycloxydim suggesting that non-target site resistance (NTSR) was present in all populations including the ones where TSR were found. The seed bioassay was not a suitable method for detecting resistance to the residual herbicides pendimethalin and prosulfocarb. The whole plant dose response experiment results confirmed the results of the seed bioassay for fenoxaprop-P and cycloxydim. Three and two out of seven populations were also resistant to flupyrsulfuron and pendimethalin, respectively, while all resistant populations were susceptible to mesosulfuron + iodosulfuron. The widespread occurrence of particularly NTSR is a severe challenge to the effective management of A. myosuroides. In Denmark this challenge is even more prominent due to few modes of action being available for A. myosuroides control mainly due to national regulation on groundwater protection.

  • A review of the effects of crop agronomy on the management of Alopecurus myosuroides
    Weed Research, 2013
    Co-Authors: P. J. W. Lutman, S. R. Moss, S. K. Cook, S. J. Welham
    Abstract:

    Summary This study reviews 52 field experiments, mostly from the UK, studying the effects of cultivation techniques, sowing date, crop density and cultivar choice on Alopecurus myosuroides infestations in cereal crops. Where possible, a statistical meta-analysis has been used to calculate average responses to the various cultural practices and to estimate their variability. In 25 experiments, mouldboard ploughing prior to sowing winter cereals reduced A. myosuroides populations by an average of 69%, compared with non-inversion tillage. Delaying drilling from September to the end of October decreased weed plant densities by approximately 50%. Sowing wheat in spring achieved an 88% reduction in A. myosuroides plant densities compared with autumn sowing. Increasing winter wheat crop density above 100 plants m−2 had no effect on weed plant numbers, but reduced the number of heads m−2 by 15% for every additional increase in 100 crop plants, up to the highest density tested (350 wheat plants m−2). Choosing more competitive cultivars could decrease A. myosuroides heads m−2 by 22%. With all cultural practices, outcomes were highly variable and effects inconsistent. Farmers are more likely to adopt cultural measures and so reduce their reliance on herbicides, if there were better predictions of likely outcomes at the individual field level.

  • Characterisation and molecular basis of ALS inhibitor resistance in the grass weed Alopecurus myosuroides
    Weed Research, 2008
    Co-Authors: R. Marshall, S. R. Moss
    Abstract:

    Summary Several UK populations of the grass weed Alopecurus myosuroides were identified where high proportions of individuals showed resistance to the acetolactate synthase (ALS)-inhibiting herbicides, mesosulfuron-methyl + iodosulfuron-methyl sodium mixture and sulfometuron-methyl. Screening with sulfometuron, followed by DNA sequencing of the ALS gene from resistant and susceptible individuals, led to the identification of eight populations where a single point mutation segregated with resistance to sulfometuron. All highly resistant individuals from seven of eight populations showed a single-nucleotide polymorphism (SNP) in the first position of the Pro197 codon of an A. myosuroides ALS gene, conferring a predicted proline to threonine target-site change. One population showed resistant individuals with single-nucleotide polymorphism in the second position of the Trp574 codon, conferring a predicted tryptophan to leucine substitution. No other mutations segregating with resistance were found. Enzyme assays confirmed that resistance was due to an altered form of ALS enzyme, which was less susceptible to inhibition by sulfonylureas, making this one of the first fully characterised cases of ALS target-site resistance in a European grass weed. Increased information regarding the nature and distribution of ALS target-site mutation may help support sustainable management strategies, allowing continued use of mesosulfuron + iodosulfuron against this weed in the UK.

  • herbicide resistance to mesosulfuron iodosulfuron in Alopecurus myosuroides black grass
    Communications in agricultural and applied biological sciences, 2008
    Co-Authors: R I Hull, R. Marshall, L V Tatnell, S. R. Moss
    Abstract:

    A formulated mixture of two sulfonylurea herbicides, mesosulfuron and iodosulfuron, combined with the safener mefenpyr-diethyl ('Atlantis') is being used extensively in Europe and there is concern that resistance will evolve in Alopecurus myosuroides (black-grass). Glasshouse screening bioassays showed that the best single discriminating dose for detecting resistance is the UK field rate of 12 g mesosulfuron + 2.4 g iodosulfuron ha(-1) applied at the 3 leaf stage, with herbicidal effects recorded 4 weeks later. Using this methodology with 466 UK seed samples, resistance was confirmed on a total of 24 farms in 11 counties by 2005, 81 farms in 19 counties by 2006 and 133 farms in 21 counties by 2007. Cultural histories for 10 resistant (R) and 7 susceptible (S) fields were obtained. Winter cereals were grown in 73% R/ 71% S years and a mean of 3.0 grass-weed active ingredients applied per year in both R and S fields. Four herbicide classes dominated, comprising almost 80% of all applications: ALS inhibitors 17% R/ 21% S; ACCase inhibitors 19% R/ 17% S; substituted ureas 18% R/ 10% S; dinitroanilines 25% R/ 30% S. Consequently, ALS inhibitor use was not excessive and field histories were not a reliable indicator of resistance risk. DNA sequencing of the ALS gene from resistant and susceptible individuals of nine populations was used to identify resistance mechanisms. All highly resistant individuals from seven populations showed a single nucleotide polymorphism in the first position of the Pro197 codon of an A. myosuroides ALS gene. One population showed resistant individuals with a single nucleotide polymorphism in the second position of the Trp574 codon. Consequently ALS target site resistance was confirmed in eight of the nine populations studied in detail.

  • quantifying the dormancy of Alopecurus myosuroides seeds produced by plants exposed to different soil moisture and temperature regimes
    Weed Research, 2006
    Co-Authors: A J Swain, S. K. Cook, Z S Hughes, S. R. Moss
    Abstract:

    In pot studies, seeds of Alopecurus myosuroides were less dormant when produced under warm and dry, than under cool and wet conditions. The temperature to which plants were exposed had a greater effect on seed dormancy than soil moisture. The timing of temperature stress had a big impact on initial seed dormancy. The critical period was during seed maturation, irrespective of temperature conditions during the earlier phase of panicle emergence and anthesis. A much higher proportion (57-62%) of seeds collected from fields in 2001, 2003 and 2005 were non-dormant than in 2002 and 2004 (22-28%). Meteorological records showed that the mid-June to mid-July periods in England for 2001, 2003 and 2005 were warmer than average but in 2002 and 2004 were cooler than average. Consequently, results for samples collected from fields support those from experiments conducted under more controlled conditions. Studies in outdoor micro-plots showed that the differences in seed dormancy recorded with freshly produced seed did affect the rate of germination in the field, 2-3 months after shedding.

Annick Matejicek - One of the best experts on this subject based on the ideXlab platform.

  • Status of black-grass (Alopecurus myosuroides) resistance to acetyl-coenzyme A carboxylase inhibitors in France
    Weed Research, 2007
    Co-Authors: Christophe Delye, Jean-philippe Guillemin, Annick Matejicek, Yosra Menchari, Séverine Michel, Christine Camilleri, Bruno Chauvel
    Abstract:

    We assessed the contributions of target site- and non-target site-based resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC-inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine-to-leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC-inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism-based resistance to ACC-inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non-target site-based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC-inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism-based resistance mechanisms conferring broad-spectrum cross-resistance

  • multiple origins for black grass Alopecurus myosuroides huds target site based resistance to herbicides inhibiting acetyl coa carboxylase
    Pest Management Science, 2004
    Co-Authors: Christophe Delye, Annick Matejicek, Cecile Straub, Séverine Michel
    Abstract:

    We have investigated the process of evolution of target-site-based resistance to herbicides inhibiting acetyl-CoA carboxylase (ACCase) in nine French populations of black-grass (Alopecurus myosuroides Huds). To date, two different ACCase resistant alleles are known. One contains an isoleucine-to-leucine substitution at position 1781, the second contains an isoleucine-to-asparagine substitution at position 2041. Using phylogenetic analysis of ACCase sequences, we showed that 1781Leu ACCase alleles evolved from four independent origins in the nine black-grass populations studied, while 2041Asn ACCase alleles evolved from six independent origins. No geographical structure of black-grass populations was revealed. This implies that these populations, although geographically distant, are, or have until recently been, connected by gene flows. Comparison of biological data obtained from herbicide sensitivity bioassay and molecular data showed that distinct resistance mechanisms often exist in a single black-grass population. Accumulation of different resistance mechanisms in a single plant was also demonstrated. We conclude that large-scale evolution of resistance to herbicides in black-grass is a complex phenomenon, resulting from the independent selection of various resistance mechanisms in local black-grass populations undergoing contrasted herbicide and agronomical selection pressures, and connected by gene flows whose parameters remain to be determined. Copyright © 2003 Society of Chemical Industry

  • pcr based detection of resistance to acetyl coa carboxylase inhibiting herbicides in black grass Alopecurus myosuroides huds and ryegrass lolium rigidum gaud
    Pest Management Science, 2002
    Co-Authors: Christophe Delye, Annick Matejicek, Jacques Gasquez
    Abstract:

    A simple method based upon allele-specific PCR was developed to detect an isoleucine-leucine substitution in the gene encoding chloroplastic acetyl-coenzyme A carboxylase (ACCase) in two gramineous weeds: Lolium rigidum Gaud and Alopecurus myosuroides Huds. Analysis of 1800 A myosuroides and 750 L rigidum seedlings showed that the presence of ACCase leucine allele(s) conferred cross-resistance to the cyclohexanedione herbicide cycloxydim and to the aryloxyphenoxypropionate herbicides fenoxaprop-P-ethyl and diclofop-methyl. Seedlings containing ACCase leucine allele(s) could be either sensitive or resistant to the aryloxyphenoxypropionate herbicides haloxyfop-P-methyl and clodinafop-propargyl. Successful detection of resistant plants in a field population of A myosuroides was achieved using this PCR assay. Using it with basic molecular biology laboratory equipment, the presence of resistant leucine ACCase allele(s) can be detected within one working day.

  • snp markers for black grass Alopecurus myosuroides huds genotypes resistant to acetyl coa carboxylase inhibiting herbicides
    Theoretical and Applied Genetics, 2002
    Co-Authors: Christophe Delye, E Calmes, Annick Matejicek
    Abstract:

    Chloroplastic acetyl CoA-carboxylase (ACCase) is the target of widely used, specific graminicide herbicides: cyclohexanediones (CHDs) and aryloxyphenoxypropionates (APPs). Resistance to these compounds is a worldwide, increasing problem. Population genetic studies aimed at understanding the dynamics of this situation and the diffusion of resistance genes within and between weed populations are challenging because biological assays are not adequate for this purpose, and because different mechanisms of resistance confer a similar resistance phenotype. Molecular markers for specifically detecting resistance genes are therefore urgently needed to conduct such studies. For this purpose, we cloned and sequenced the whole gene encoding chloroplastic ACCase in Alopecurus myosuroides Huds. (Black-grass). We identified two point mutations at nucleotide 5,341 that both cause an isoleucine-leucine substitution at position 1,781. Three bi-directional allele-specific PCR assays were developed, each detecting two distinct ACCase alleles with a single PCR reaction. The sensitivity of 1,190 seedlings of A. myosuroides to one CHD and one APP was determined. Genotyping revealed that, although resistant plants were only selected by APPs, the 1,781Leu ACCase allele is a widespread, dominant gene of resistance to both APPs and CHDs. No other ACCase allele associated with resistance could be identified in this work. Useful applications of allele-specific PCR markers are population genetic studies as well as routine molecular diagnosis of herbicide resistance.

Bruno Chauvel - One of the best experts on this subject based on the ideXlab platform.

  • DNA Analysis of Herbarium Specimens of the Grass Weed Alopecurus myosuroides Reveals Herbicide Resistance Pre-Dated Herbicides
    PLoS ONE, 2013
    Co-Authors: Christophe Delye, Chrystel Deulvot, Bruno Chauvel
    Abstract:

    Acetyl-CoA carboxylase (ACCase) alleles carrying one point mutation that confers resistance to herbicides have been identified in arable grass weed populations where resistance has evolved under the selective pressure of herbicides. In an effort to determine whether herbicide resistance evolves from newly arisen mutations or from standing genetic variation in weed populations, we used herbarium specimens of the grass weed Alopecurus myosuroides to seek mutant ACCase alleles carrying an isoleucine-to-leucine substitution at codon 1781 that endows herbicide resistance. These specimens had been collected between 1788 and 1975, i.e., prior to the commercial release of herbicides inhibiting ACCase. Among the 734 specimens investigated, 685 yielded DNA suitable for PCR. Genotyping the ACCase locus using the derived Cleaved Amplified Polymorphic Sequence (dCAPS) technique identified one heterozygous mutant specimen that had been collected in 1888. Occurrence of a mutant codon encoding a leucine residue at codon 1781 at the heterozygous state was confirmed in this specimen by sequencing, clearly demonstrating that resistance to herbicides can pre-date herbicides in weeds. We conclude that point mutations endowing resistance to herbicides without having associated deleterious pleiotropic effects can be present in weed populations as part of their standing genetic variation, in frequencies higher than the mutation frequency, thereby facilitating their subsequent selection by herbicide applications.

  • non target site based resistance should be the centre of attention for herbicide resistance research Alopecurus myosuroides as an illustration
    Weed Research, 2011
    Co-Authors: Christophe Delye, Bruno Chauvel, Jeanne Gardin, Karelle Boucansaud, Cecile Petit
    Abstract:

    Delye C, Gardin JAC, Boucansaud K, Chauvel B & Petit C (2011). Non-target-site-based resistance should be the centre of attention for herbicide resistance research: Alopecurus myosuroides as an illustration. Weed Research51, 433–437. Summary Non-target-site-based resistance (NTSR) mechanisms can confer unpredictable resistance to herbicides with different chemistries or modes of action. In two French fields, 18% and 40% individual plants of Alopecurus myosuroides (black-grass), respectively, were resistant via NTSR to all the most effective herbicides approved for A. myosuroides control in wheat (fenoxaprop, clodinafop, pinoxaden, iodosulfuron+mesosulfuron and pyroxsulam) and to the broad-leaf-selective herbicide quizalofop. Pinoxaden and pyroxsulam had never been applied to these populations. In the absence of new herbicide modes of action, this renders a purely chemical control of A. myosuroides in winter cereals much more complex in these fields. A segregation analysis showed that multi-resistant phenotypes were endowed by multiple NTSR genes, underlining the complexity of NTSR. Yet, despite the threat posed to weed control, our lack of knowledge on NTSR is obvious. NTSR should therefore become the priority in herbicide resistance research.

  • geographical variation in resistance to acetyl coenzyme a carboxylase inhibiting herbicides across the range of the arable weed Alopecurus myosuroides black grass
    New Phytologist, 2010
    Co-Authors: Christophe Delye, Bruno Chauvel, Jean-philippe Guillemin, Séverine Michel, Aurelie Berard, Dominique Brunel, Fabrice Dessaint, Valerie Le Corre
    Abstract:

    Summary • The geographical structure of resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACCase) was investigated in the weed Alopecurus myosuroides (black-grass) across its geographical range to gain insight into the process of plant adaptation in response to anthropogenic selective pressures occurring in agricultural ecosystems. • We analysed 297 populations distributed across six countries in A. myosuroides’ main area of occupancy. The frequencies of plants resistant to two broadly used ACCase inhibitors and of seven mutant, resistant ACCase alleles were assessed using bioassays and genotyping, respectively. • Most of the resistance was not endowed by mutant ACCase alleles. Resistance and ACCase allele distribution patterns were characterized by mosaicism. The prevalence of resistance and of ACCase alleles differed among countries. • Resistance clearly evolved by redundant evolution of a set of resistance alleles or genes, most of which remain unidentified. Resistance in A. myosuroides was shaped by variation in the herbicide selective pressure at both the individual field level and the national level.

  • Evolution of a herbicide-resistant population of Alopecurus myosuroides Huds. in a long-term cropping system experiment
    Crop Protection, 2009
    Co-Authors: Bruno Chauvel, Jean-philippe Guillemin, Nathalie Colbach
    Abstract:

    Abstract Due to heavy reliance on herbicides and a lack of cultural control measures, herbicide-resistant populations of Alopecurus myosuroides Huds. (blackgrass) appeared in the early 1990s in winter cereal rotations in France and in Europe. The aim of the present study was to analyse the effects of different cropping systems on an aryloxy-phenoxypropionate herbicide-resistant population in a field trial. Two crop rotations, one consisting exclusively of winter crops and another including spring crops, were assessed over a six-year period. The rotations were combined with different cultural practices including mouldboard ploughing, delayed sowing, and efficient herbicides for controlling resistant plants. A. myosuroides densities decreased in all the cropping systems, but the weed management was most effective when herbicides were combined with non-chemical practices. Rotation with an alternation of spring and winter crops was the most efficient solution against A. myosuroides . Moreover, during the six years, the percentage of resistant plants in different crop rotations was estimated independently of the cropping systems. This proportion did not vary during the six years of the experiment, suggesting that the resistance gene persisted, despite the removal of selection pressure by the aryloxy-phenoxypropionate herbicides.

  • Status of black-grass (Alopecurus myosuroides) resistance to acetyl-coenzyme A carboxylase inhibitors in France
    Weed Research, 2007
    Co-Authors: Christophe Delye, Jean-philippe Guillemin, Annick Matejicek, Yosra Menchari, Séverine Michel, Christine Camilleri, Bruno Chauvel
    Abstract:

    We assessed the contributions of target site- and non-target site-based resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC-inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine-to-leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC-inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism-based resistance to ACC-inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non-target site-based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC-inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism-based resistance mechanisms conferring broad-spectrum cross-resistance

Séverine Michel - One of the best experts on this subject based on the ideXlab platform.

  • geographical variation in resistance to acetyl coenzyme a carboxylase inhibiting herbicides across the range of the arable weed Alopecurus myosuroides black grass
    New Phytologist, 2010
    Co-Authors: Christophe Delye, Bruno Chauvel, Jean-philippe Guillemin, Séverine Michel, Aurelie Berard, Dominique Brunel, Fabrice Dessaint, Valerie Le Corre
    Abstract:

    Summary • The geographical structure of resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACCase) was investigated in the weed Alopecurus myosuroides (black-grass) across its geographical range to gain insight into the process of plant adaptation in response to anthropogenic selective pressures occurring in agricultural ecosystems. • We analysed 297 populations distributed across six countries in A. myosuroides’ main area of occupancy. The frequencies of plants resistant to two broadly used ACCase inhibitors and of seven mutant, resistant ACCase alleles were assessed using bioassays and genotyping, respectively. • Most of the resistance was not endowed by mutant ACCase alleles. Resistance and ACCase allele distribution patterns were characterized by mosaicism. The prevalence of resistance and of ACCase alleles differed among countries. • Resistance clearly evolved by redundant evolution of a set of resistance alleles or genes, most of which remain unidentified. Resistance in A. myosuroides was shaped by variation in the herbicide selective pressure at both the individual field level and the national level.

  • Status of black-grass (Alopecurus myosuroides) resistance to acetyl-coenzyme A carboxylase inhibitors in France
    Weed Research, 2007
    Co-Authors: Christophe Delye, Jean-philippe Guillemin, Annick Matejicek, Yosra Menchari, Séverine Michel, Christine Camilleri, Bruno Chauvel
    Abstract:

    We assessed the contributions of target site- and non-target site-based resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC-inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine-to-leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC-inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism-based resistance to ACC-inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non-target site-based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC-inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism-based resistance mechanisms conferring broad-spectrum cross-resistance

  • Weed response to herbicides: regional-scale distribution of herbicide resistance alleles in the grass weed Alopecurus myosuroides
    New Phytologist, 2006
    Co-Authors: Yosra Menchari, Séverine Michel, Christine Camilleri, Dominique Brunel, Fabrice Dessaint, Valérie Le Corre, Christophe Delye
    Abstract:

    Effective herbicide resistance management requires an assessment of the range of spatial dispersion of resistance genes among weed populations and identification of the vectors of this dispersion. In the grass weed Alopecurus myosuroides (black-grass), seven alleles of the acetyl-CoA carboxylase (ACCase) gene are known to confer herbicide resistance. Here, we assessed their respective frequencies and spatial distribution on two nested geographical scales (the whole of France and the French administrative district of Côte d'Or) by genotyping 13 151 plants originating from 243 fields. Genetic variation in ACCase was structured in local populations at both geographical scales. No spatial structure in the distribution of resistant ACCase alleles and no isolation by distance were detected at either geographical scale investigated. These data, together with ACCase sequencing and data from the literature, suggest that evolution of A. myosuroides resistance to herbicides occurred at the level of the field or group of adjacent fields by multiple, independent appearances of mutant ACCase alleles that seem to have rather restricted spatial propagation. Seed transportation by farm machinery seems the most likely vector for resistance gene dispersal in A. myosuroides.

  • multiple origins for black grass Alopecurus myosuroides huds target site based resistance to herbicides inhibiting acetyl coa carboxylase
    Pest Management Science, 2004
    Co-Authors: Christophe Delye, Annick Matejicek, Cecile Straub, Séverine Michel
    Abstract:

    We have investigated the process of evolution of target-site-based resistance to herbicides inhibiting acetyl-CoA carboxylase (ACCase) in nine French populations of black-grass (Alopecurus myosuroides Huds). To date, two different ACCase resistant alleles are known. One contains an isoleucine-to-leucine substitution at position 1781, the second contains an isoleucine-to-asparagine substitution at position 2041. Using phylogenetic analysis of ACCase sequences, we showed that 1781Leu ACCase alleles evolved from four independent origins in the nine black-grass populations studied, while 2041Asn ACCase alleles evolved from six independent origins. No geographical structure of black-grass populations was revealed. This implies that these populations, although geographically distant, are, or have until recently been, connected by gene flows. Comparison of biological data obtained from herbicide sensitivity bioassay and molecular data showed that distinct resistance mechanisms often exist in a single black-grass population. Accumulation of different resistance mechanisms in a single plant was also demonstrated. We conclude that large-scale evolution of resistance to herbicides in black-grass is a complex phenomenon, resulting from the independent selection of various resistance mechanisms in local black-grass populations undergoing contrasted herbicide and agronomical selection pressures, and connected by gene flows whose parameters remain to be determined. Copyright © 2003 Society of Chemical Industry