Weed response to herbicides: regional‐scale distribution of herbicide resistance alleles in the grass weedAlopecurus myosuroides

Abstract

Summary• 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 .

Effect of herbicide resistance endowing three ACCase mutations on seed germination and viability in American slough grass ( Beckmannia syzigachne Steud. Fernald)

“…Alopecurus myosuroides containing 1781Leu/ Leu ACCase also showed a fitness advantage in seed germination (Délye et al, 2013). In addition, wide spread of Ile1781Leu ACCase in L. rigidum and across grass species may suggest that Ile1781Leu ACCase usually cause no fitness cost (Délye et al, 2005;Zhang and Powles, 2006;Menchari et al, 2006;Liu et al, 2007;Yu et al, 2007). In this paper, seeds containing homozygous 1781Leu/Leu ACCase showed a fitness advantage under salt and osmotic stress, but no fitness variation in optimal experimental condition.…”

Multiple Resistance to Acetyl Coenzyme A Carboxylase and Acetolactate Synthase Inhibiting Herbicides in Tunisian Ryegrass Populations (Lolium rigidum)

“…In previous studies, these mutations are the most frequently observed in different grass weed species [19,20].…”

Using next‐generation sequencing to detect mutations endowing resistance to pesticides: application to acetolactate‐synthase (ALS)‐based resistance in barnyard grass, a polyploid grass weed

“…19,20 Following technology evolution, allele-specific PCR has been at the basis of 'hi-tech', high-throughput assays implementing quantitative PCR. 21,22 Other genotyping techniques allowing high-throughput detection of mutations at known positions have also been used to develop pesticide resistance diagnosis, such as MALDI-TOF, 23 TaqMan, 24,25 SimpleProbe, 26 DNA microarrays 27 or SNaPshot. 28 A common feature of all the techniques described above is that they only provide information about the mutation(s) present at a given nucleotide position or codon, which generally requires identification of the mutation(s) in question beforehand.…”