Characterisation of target-site resistance to ACCase-inhibiting herbicides in the weed Alopecurus myosuroides (black-grass).
Resistance to aryloxyphenoxypropionate (AOPP), cyclohexanedione (CHD) and phenylurea herbicides was determined in UK populations of Alopecurus myosuroides Huds. Two populations (Oxford AA1, Notts. A1) were highly resistant (Resistance indices 13-->1000) to the AOPP and CHD herbicides fenoxaprop, diclofop, fluazifop-P and sethoxydim, but only marginally resistant to the phenylurea, chlorotoluron. Analyses of acetyl coenzyme A carboxylase (ACCase) activity showed that an insensitive ACCase conferred resistance to all the AOPP/CHD herbicides investigated. Another population, Oxford S1, showed no resistance to sethoxydim at the population level, but contained a small proportion of plants (<10%) with an insensitive ACCase. Genetic studies on the Notts A1 and Oxford S1 populations demonstrated that target site resistance conferred by an insensitive ACCase is monogenic, nuclearly inherited with the resistant allele showing complete dominance. Investigations of the molecular basis of resistance in the Notts A1 population showed that sethoxydim resistance in A myosuroides was associated with the substitution of an isoleucine in susceptible with a leucine in resistant plants, which has also been found in three other resistant grass-weed species (Setaria viridis (L) Beauv, Avena fatua L, Lolium rigidum Gaud).
Moss
Stephen R
SR
Division of Plant and Invertebrate Ecology, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK. Stephen.Moss@bbsrc.ac.uk
Cocker
Kay M
KM
Brown
Amanda C
AC
Hall
Linda
L
Field
Linda M
LM
D000103:Acetyl-CoA Carboxylase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000187:drug effects; D003512:Cyclohexanones / Q000378:metabolism / Q000633:toxicity; D004095:Dihydropyridines / Q000378:metabolism / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000235:genetics; D004780:Environment, Controlled; D005816:Genetic Complementation Test; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides / Q000378:metabolism / Q000633:toxicity*; D010080:Oxazoles / Q000378:metabolism / Q000633:toxicity; D010647:Phenyl Ethers / Q000378:metabolism / Q000633:toxicity; D010671:Phenylurea Compounds / Q000378:metabolism / Q000633:toxicity; D006109:Poaceae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D011422:Propionates / Q000378:metabolism / Q000633:toxicity
D003512:Cyclohexanones; D004095:Dihydropyridines; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides; D010080:Oxazoles; D010647:Phenyl Ethers; D010671:Phenylurea Compounds; D011422:Propionates; C049437:sethoxydim; C416661:fenoxaprop ethyl; C050582:fluazifop; C012891:dichlorfop-methyl; D000103:Acetyl-CoA Carboxylase; C007033:chlortoluron