Pest Management Science (2012) 68, 1241-1247

Huaiwu Tang, Jun Li, Liyao Dong, Aibin Dong, Bo Lü and Xudong Zhu (2012)
Molecular bases for resistance to acetyl-coenzyme A carboxylase inhibitor in Japanese foxtail (Alopecurus japonicus)
Pest Management Science 68 (9), 1241-1247
Abstract: BACKGROUND: Haloxyfop-R-methyl is a widely used herbicide to control Poaceae weeds. Alopecurus japonicus, a widespread annual grass, can no longer be controlled by haloxyfop-R-methyl after continuous use of this herbicide for several years.
RESULTS: Dose-response experiments have established that the Js-R biotype of A. japonicas has evolved resistance to aryloxyphenoxypropionates (APPs). Target-site enzyme sensitivity experiments have established that the haloxyfop (free acid) rate causing 50% inhibition of acetyl-CoA carboxylase (ACCase) activity (I₅₀) for the resistant (Js-R) biotype is 11 times higher than that for the susceptible (Js-S) biotype. In many cases, resistance to ACCase-inhibiting herbicides is due to a resistant ACCase enzyme. Full-length DNA and mRNA sequences of the plastidic ACCase gene were amplified. Eight single-nucleotide differences were detected in this region. Four of the nucleotide changes were silent mutations. However, the other four nucleotide mutations caused four amino acid substitutions, replacing Arg-1734 with Gly, Met-1738 with Leu, Thr-1739 with Ser and Ile-2041 with Asn in the R biotype respectively; the substitution at position 2041 had been reported, while the other three had not.
CONCLUSION: The ACCase in the Js-R biotype was less susceptible to haloxyfop-R-methyl than that in the Js-S biotype. Moreover, the amino acid substitution of Ile-2041 with Asn might confer resistance to haloxyfop-R-methyl in A. japonicas.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Liyao Dong

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Alopecurus japonicus (weed)