Hostname: page-component-546b4f848f-zwmfq Total loading time: 0 Render date: 2023-06-01T10:17:59.929Z Has data issue: false Feature Flags: { "useRatesEcommerce": true } hasContentIssue false

Association of the W574L ALS substitution with resistance to cloransulam and imazamox in common ragweed (Ambrosia artemisiifolia)

Published online by Cambridge University Press:  20 January 2017

Danman Zheng
Program in Physiological and Molecular Plant Biology, University of Illinois, Urbana, IL 61801
William L. Patzoldt
Department of Crop Sciences, University of Illinois, Urbana, IL 61801


Previous research revealed that resistance to cloransulam in at least one population of common ragweed was conferred by an altered herbicide target site, specifically, by a tryptophan-to-leucine amino acid substitution at position 574 (W574L) of acetolactate synthase (ALS). In this study, 22 common ragweed populations, several of which were suspected cloransulam resistant, were assayed to determine if the W574L ALS substitution was correlated with resistance to ALS inhibitors. From each population, 16 greenhouse-grown plants were treated with cloransulam, and another 16 were treated with imazamox. Plant dry weights were recorded 20 d after treatment and individual plants were considered resistant if their dry weight exceeded 50% of that of nonherbicide-treated controls. For each herbicide-treated plant, allele-specific primers were used in polymerase chain reactions to determine whether the ALS alleles contained leucine or tryptophan codons at position 574. Of the 352 plants treated with cloransulam, 70 were determined to be resistant, and all but two contained one or more Leu574 alleles. The frequency of imazamox resistance was much higher than that of cloransulam in the populations, with 149 of 352 plants identified as imazamox resistant. However, only about half (80) of the imazamox-resistant plants contained one or more Leu574 alleles. Correlation of imazamox resistance and Leu574 alleles was population dependent. ALS activity assays confirmed that imazamox resistance in plants from at least one population was due to an altered target site, even though plants from that population did not have a W574L substitution. These results lead to the conclusion that a Leu574 allele is the predominant basis for cloransulam resistance in common ragweed; however, other mechanisms of resistance to ALS inhibitors exist in some populations.

Physiology, Chemistry, and Biochemistry
Copyright © Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Literature Cited

Bradford, M. M. 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein dye binding. Anal. Biochem 72:248254.CrossRefGoogle ScholarPubMed
Burnet, M. W. M., Christopher, J. T., Holtum, J. A. M., and Powles, S. B. 1994. Identification of two mechanisms of sulfonylurea resistance within one population of rigid ryegrass (Lolium rigidum) using a selective germination medium. Weed Sci 42:468473.Google Scholar
Christopher, J. T., Powles, S. B., and Holtum, J. A. M. 1992. Resistance to acetolactate synthase-inhibiting herbicides in annual ryegrass (Lolium rigidum) involves at least two mechanisms. Plant Physiol 100:19091913.CrossRefGoogle ScholarPubMed
Christopher, J. T., Powles, S. B., Liljegren, D. R., and Holtum, J. A. M. 1991. Cross-resistance to herbicides in annual ryegrass (Lolium rigidum). II. Chlorsulfuron resistance involves a wheat like detoxification system. Plant Physiol 100:10361043.CrossRefGoogle Scholar
Doyle, J. J. and Doyle, J. L. 1990. Isolation of plant DNA from fresh tissue. Focus 12:1315.Google Scholar
Heap, I. 2004. The International Survey of Herbicide Resistant Weeds. Scholar
Kemp, M. S., Moss, S. R., and Thomas, T. H. 1990. Herbicide resistance in Alopecurus myosuroides . Pages 376393 in Green, M. B., LeBaron, H. M., and Moberg, W. K. eds. Managing Resistance to Agrochemicals. From Fundamental Research to Practical Strategies. Washington, DC: American Chemical Society.CrossRefGoogle Scholar
Patzoldt, W. L. and Tranel, P. J. 2002. Molecular analysis of cloransulam resistance in a population of giant ragweed. Weed Sci 50:299305.CrossRefGoogle Scholar
Patzoldt, W. L., Tranel, P. J., Alexander, A. L., and Schmitzer, P. R. 2001. A common ragweed population resistant to cloransulam-methyl. Weed Sci 49:485490.CrossRefGoogle Scholar
Pettersson, M., Bylund, M., and Alderborn, A. 2003. Molecular haplotype determination using allele-specific PCR and pyrosequencing technology. Genomics 82:390396.CrossRefGoogle Scholar
Saari, L. L., Cotterman, J. C., and Thill, D. C. 1994. Resistance to acetolactate synthase inhibiting herbicides. Pages 83139 in Powles, S. B. and Holtum, J.A.M. eds. Herbicide Resistance in Plants: Biology and Biochemistry. Ann Arbor, MI: Lewis.Google Scholar
Schmitzer, P. R., Eilers, R. J., and Cséke, C. 1993. Lack of cross-resistance of imazaquin-resistant Xanthium strumarium acetolactate synthase to flumetsulam and chlorimuron. Plant Physiol 103:281283.CrossRefGoogle Scholar
Schultz, M. E., Schmitzer, P. R., Alexander, A. L., and Dorich, R. A. 2000. Identification and management of resistance to ALS-inhibiting herbicides in giant ragweed (Ambrosia trifida) and common ragweed (Ambrosia artemisiifolia). Weed Sci. Soc. Am. Abstr 40:42.Google Scholar
Tranel, P. J., Jiang, W., Patzoldt, W. L., and Wright, T. R. 2004a. Intraspecific variability of the acetolactate synthase gene. Weed Sci 52:236241.CrossRefGoogle Scholar
Tranel, P. J. and Wright, T. R. 2002. Resistance of weeds to ALS-inhibiting herbicides: what have we learned? Weed Sci 50:700712.CrossRefGoogle Scholar
Tranel, P. J., Wright, T. R., and Heap, I. M. 2004b. ALS Mutations from Herbicide-resistant Weeds. Scholar
Wright, T. R., Bascomb, N. E., Sturner, S. F., and Penner, D. 1998. Biochemical mechanism and molecular basis for ALS-inhibiting herbicide resistance in sugarbeet (Beta vulgaris) somatic cell selection. Weed Sci 46:1323.Google Scholar