First report of molecular basis of resistance to imazethapyr in common lambsquarters (Chenopodium album)

Weed Science ◽  
2019 ◽  
pp. 1-6
Author(s):  
Zhaofeng Huang ◽  
Xinxin Zhou ◽  
Chaoxian Zhang ◽  
Cuilan Jiang ◽  
Hongjuan Huang ◽  
...  

Abstract Common lambsquarters (Chenopodium album L.) is one of the most troublesome weeds in soybean [Glycine max (L.) Merr.] and corn (Zea mays L.) fields in northeast China. In 2017, a C. album population that survived imazethapyr at the recommended field rate was collected from a soybean field in Heilongjiang Province in China. Experiments were conducted to determine the basis of resistance to imazethapyr and investigate the herbicide-resistance pattern in C. album. Dose–response tests showed that the resistant population (R) displayed high resistance to imazethapyr (20-fold) compared with the susceptible population (S). An in vitro acetolactate synthase (ALS) activity assay indicated that the ALS of the R population was resistant to imazethapyr compared with the ALS of the S population. Sequence analysis of the ALS gene revealed that the GCA was replaced by ACA at amino acid position 122, which resulted in an alanine to threonine substitution (Ala-122-Thr) in the R population. The R population displayed cross-resistance to thifensulfuron-methyl and flumetsulam but susceptibility to bispyribac-sodium, flucarbazone, glyphosate, mesotrione, and fomesafen. These results confirmed that the basis of imazethapyr resistance in C. album was conferred by the Ala-122-Thr substitution in the ALS enzyme. This is the first report of the target-site basis of ALS-inhibiting herbicide resistance in C. album.

Weed Science ◽  
2017 ◽  
Vol 65 (2) ◽  
pp. 239-246 ◽  
Author(s):  
Wenlei Guo ◽  
Lele Zhang ◽  
Hengzhi Wang ◽  
Qi Li ◽  
Weitang Liu ◽  
...  

Understanding the mechanism of herbicide resistance is fundamental for designing sustainable weed control strategies and exploiting herbicides rationally. Shortawn foxtail is a problem grass weed infesting several important crops in China. The repeated use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides has resulted in herbicide resistance in this weed. The ACCase gene of resistant individuals of a shortawn foxtail population (JSLS-1) has an Ile-2041-Thr mutation. F2 generation seeds, originated from the same heterozygous plant, were harvested, and two homozygous mutant (JSLS-1RR) and wild (JSLS-1SS) populations for the Ile-2041-Thr mutation were obtained. In whole plants, the JSLS-1RR population conferred high resistance to fenoxaprop and clodinafop, moderate resistance to haloxyfop, low resistance to pinoxaden, and no obvious resistance to clethodim and sethoxydim, compared with JSLS-1SS and a proven susceptible population (HNXY-1). A derived cleaved amplified polymorphic sequence (dCAPS) marker was developed to rapidly detect the rare Ile-2041-Thr mutation in the shortawn foxtail population. This is the first report of the cross-resistance pattern of Ile-2041-Thr mutation, and the robust dCAPS marker could quickly detect this mutation in shortawn foxtail.


2007 ◽  
Vol 87 (4) ◽  
pp. 965-972 ◽  
Author(s):  
H. J. Beckie ◽  
L. M. Hall ◽  
F. J. Tardif ◽  
G. Séguin-Swartz

Two stinkweed populations from southern and central Alberta were not controlled by acetolactate synthase (ALS)-inhibiting herbicides in 2000. This study reports on their cross-resistance to ALS-inhibiting herbicides, molecular basis of resistance, and inheritance of resistance. Both putative herbicide-resistant biotypes responded similarly to increasing doses of the herbicides. The biotypes were highly resistant to ethametsulfuron and exhibited a low level of resistance to metsulfuron and imazethapyr. However, both biotypes were not resistant to florasulam, a triazolopyrimidine ALS inhibitor, or sulfometuron, a non-selective sulfonylurea ALS inhibitor. The cross-resistance pattern was consistent with the confirmed target-site mutation. Sequence analysis of the ALS gene detected a Pro197Leu mutation in both biotypes. Similar to many other ALS inhibitor-resistant weed biotypes, resistance was conferred by a single dominant gene. This study confirms the first global occurrence of herbicide resistance in this species. Key words: ALS-inhibitor resistance, ALS sequence, herbicide resistance, target-site mutation


Weed Science ◽  
2017 ◽  
Vol 65 (4) ◽  
pp. 452-460 ◽  
Author(s):  
Haitao Gao ◽  
Jiaxing Yu ◽  
Lang Pan ◽  
Xibao Wu ◽  
Liyao Dong

Keng stiffgrass is a serious farmland grass weed distributed globally in winter wheat fields and rice–wheat double-cropping areas. The intensive use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides has led to the evolution of resistance in a growing number of grass weeds. In this study, whole-plant pot bioassay experiments were conducted to establish that a Keng stiffgrass population from eastern China, JYJD-2, has evolved high-level resistance to fenoxaprop-P-ethyl and moderate resistance to quizalofop-P-ethyl and pinoxaden. Using the derived cleaved amplified polymorphic sequence method, a tryptophan-to-cysteine mutation at codon position 1999 (W1999C) was detected in the ACCase gene of the resistant population JYJD-2. Of the 100 JYJD-2 plants tested, we found 47 heterozygous resistant and 53 homozygous sensitive individuals. In vitro ACCase assays revealed that the IC50value of the ACCase activity of the resistant population JYJD-2 was 6.48-fold higher than that of the susceptible population JYJD-1. To the best of our knowledge, this is the first report of the occurrence of W1999C mutation in the ACCase gene of fenoxaprop-P-ethyl–resistant Keng stiffgrass. This study confirmed the resistance of Keng stiffgrass to the ACCase inhibitor fenoxaprop-P-ethyl, cross-resistance to other ACCase inhibitors, and the resistance being conferred by specific ACCase point mutations at amino acid position 1999.


2013 ◽  
Vol 31 (4) ◽  
pp. 867-874 ◽  
Author(s):  
E. Xavier ◽  
M.C. Oliveira ◽  
M.M. Trezzi ◽  
R.A. Vidal ◽  
F. Diesel ◽  
...  

The objective of this study was to determine the activity of the enzyme acetolactate synthase in biotypes of wild poinsettia (Euphorbia heterophylla) with multiple resistance to ALS- and Protox- inhibitors in the presence and absence of imazapyr, imazethapyr and nicosulfuron. We conducted in vitro assay of ALS enzyme extracted from plants of Vitorino, Bom Sucesso do Sul and Medianeira biotypes (with multiple resistance) and a susceptible population in the absence and presence of imazapyr, imazethapyr and nicosulfuron. In the absence of herbicides, biotypes with multiple resistance showed higher affinity for the substrate of the enzyme compared with the susceptible population. The herbicides imazapyr, imazethapyr and nicosulfuron had little effect on the enzyme activity of ALS-resistant biotypes and, conversely, high inhibitory effect on ALS of the susceptible population. Resistance factors were very high, greater than 438, 963 and 474 for Vitorino, Bom Sucesso do Sul and Medianeira biotypes, respectively. The resistance to ALS inhibitors is due to the insensitivity of ALS to herbicides of both imidazolinone and sulfonylurea groups, characterizing a cross-resistance.


2012 ◽  
Vol 52 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Ilias Travlos

Evaluation of Herbicide-Resistance Status on Populations of Littleseed Canarygrass (Phalaris MinorRetz.) from Southern Greece and Suggestions for their Effective ControlIn 2010, a survey was conducted in the wheat fields of a typical cereal-producing region of Greece to establish the frequency and distribution of herbicide-resistant littleseed canarygrass (Phalaris minorRetz.). In total, 73 canarygrass accessions were collected and screened in a field experiment with several herbicides commonly used to control this weed. Most of the weed populations were classed as resistant (or developing resistance) to the acetyl-CoA varboxylase (ACCase)-inhibiting herbicide diclofop, while resistance to clodinafop was markedly lower. The results of the pot experiments showed that some of the canary populations were found to have a very high level of diclofop resistance (resistance index up to 12.4), while cross resistance with other herbicides was also common. The levels of resistance and cross resistance patterns among populations varied along with the different amounts and times of selection pressure. Such variation indicated either more than one mechanism of resistance or different resistance mutations in these weed populations. The population which had the highest diclofop resistance level, showed resistance to all aryloxyphenoxypropinate (APP) herbicides applied and non-ACCase inhibitors. Alternative ACCase-inhibiting herbicides, such as pinoxaden remain effective on the majority of the tested canarygrass populations, while the acetolactate synthase (ALS)-inhibiting herbicide mesosulfuron + iodosulfuron could also provide some solutions. Consequently, there is an opportunity to effectively control canarygrass by selecting from a wide range of herbicides. It is the integration of agronomic practices with herbicide application, which helps in effective management ofP. minorand particularly its resistant populations.


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 24-29 ◽  
Author(s):  
Terry R. Wright ◽  
Donald Penner

Acetolactate synthase (ALS)-inhibiting herbicide carryover in soil can severely affect sugarbeets grown in the year(s) following application. Two newly developed imidazolinone-resistant (IMI-R) sugarbeet somatic cell selections (Sir-13 and 93R30B) were examined for magnitude of resistance and extent of cross-resistance to other classes of ALS inhibitors and compared to a previously developed sulfonylurea-resistant (SU-R) selection, Sur. In vitro shoot culture tests indicated Sir-13 resistance was specific to imidazolinone (IMI) herbicides at approximately a 100-fold resistance compared to the sensitive control sugarbeet. Sur was 10,000-fold resistant to the sulfonylurea (SU) herbicide, chlorsulfuron, and 40-fold resistant to the triazolopyrimidine sulfonanilide (TP) herbicide, flumetsulam, but not cross-resistant to the IMI herbicides. 93R30B was selected for IMI-R from a plant homozygous for the SU-R allele,Sur, and displayed similar in vitro SU-R and TP-R as Sur, but also displayed a very high resistance to various IMI herbicides (400- to 3,600-fold). Compared to the sensitive control, Sir-13 was 300- and > 250-fold more resistant to imazethapyr and imazamox residues in soil, respectively. Response by whole plants to postemergence herbicide applications was similar to that observed in shoot cultures. Sir-13 exhibited > 100-fold resistance to imazethapyr as well as imazamox, and 93R30B showed > 250-fold resistance to both herbicides. 93R30B showed great enough resistance to imazamox to merit consideration of imazamox for use as a herbicide in these sugarbeets. Sir-13 showed a two- to threefold higher level of resistance in the homozygous vs. heterozygous state, indicating that like most ALS-inhibitor resistance traits, it was semidominantly inherited.


Weed Science ◽  
2019 ◽  
Vol 67 (6) ◽  
pp. 605-612 ◽  
Author(s):  
Xiangying Liu ◽  
Shihai Xiang ◽  
Tao Zong ◽  
Guolan Ma ◽  
Lamei Wu ◽  
...  

AbstractThe widespread, rapid evolution of herbicide-resistant weeds is a serious and escalating agronomic problem worldwide. During China’s economic boom, the country became one of the most important herbicide producers and consumers in the world, and herbicide resistance has dramatically increased in the past decade and has become a serious threat to agriculture. Here, following an evidence-based PRISMA (preferred reporting items for systematic reviews and meta-analyses) approach, we carried out a systematic review to quantitatively assess herbicide resistance in China. Multiple weed species, including 26, 18, 11, 9, 5, 5, 4, and 3 species in rice (Oryza sativa L.), wheat (Triticum aestivum L.), soybean [Glycine max (L.) Merr.], corn (Zea mays L.), canola (Brassica napus L.), cotton (Gossypium hirsutum L.)., orchards, and peanut (Arachis hypogaea L.) fields, respectively, have developed herbicide resistance. Acetolactate synthase inhibitors, acetyl-CoA carboxylase inhibitors, and synthetic auxin herbicides are the most resistance-prone herbicides and are the most frequently used mechanisms of action, followed by 5-enolpyruvylshikimate-3-phosphate synthase inhibitors and protoporphyrinogen oxidase inhibitors. The lack of alternative herbicides to manage weeds that exhibit cross-resistance or multiple resistance (or both) is an emerging issue and poses one of the greatest threats challenging the crop production and food safety both in China and globally.


Weed Science ◽  
2019 ◽  
Vol 67 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Jiapeng Fang ◽  
Tingting Liu ◽  
Yuhua Zhang ◽  
Jun Li ◽  
Liyao Dong

AbstractBarnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is acknowledged to be the most troublesome weed in rice fields in Anhui and Jiangsu provinces of China. It cannot be effectively controlled using certain acetolactate synthase (ALS)-inhibiting herbicides, including penoxsulam. Echinochloa crus-galli samples with suspected resistance to penoxsulam were collected to identify the target site–based mechanism underlying this resistance. Populations AXXZ-2 and JNRG-2 showed 33- and 7.3-fold resistance to penoxsulam, respectively, compared with the susceptible JLGY-3 population. Cross-resistance to other ALS inhibitors was reported in AXXZ-2 but not in JNRG-2, and occasionally showed higher sensitivity than JLGY-3. In vitro ALS activity assays revealed that penoxsulam concentrations required to inhibit 50% of ALS activity were 11 and 5.2 times greater in AXXZ-2 and JNRG-2, respectively, than in JLGY-3. DNA and predicted amino acid sequence analyses of ALS revealed Ala-205-Val and Ala-122-Gly substitutions in AXXZ-2 and JNRG-2, respectively. Our results indicate that these substitutions in ALS are at least partially responsible for resistance to penoxsulam.


2019 ◽  
Vol 37 ◽  
Author(s):  
F. MARIANI ◽  
S.A. SENSEMAM ◽  
L. VARGAS ◽  
D. AGOSTINETO ◽  
L.A. ÁVILA ◽  
...  

ABSTRACT: Ryegrass(Lolium multiflorum)is one of the most worrisome species with regard to herbicide resistance. This study aimed at characterizing the acetolactate synthase (ALS) enzyme activity of resistant biotypes (NC and AR) and susceptible biotypes to iodosulfuron-methyl-sodium (iodosulfuron). Different concentrations of pyruvate (1, 10, 20, 40, 60, 80 and 100 mM), of iodosulfuron (0 to 100 µM for the resistant biotypes and 0 to 0.5 µM for the susceptible biotype) and concentrations of valine, leucine and isoleucine (0, 0.001, 0.01, 0.1, 1, 10 and 100 mM) were used for the in vitro characterization. According to the results, the Michaelis constant (Km) values (pyruvate) for the assessed biotypes were similar. With iodosulfuron, resistant biotypes needed 395 to 779 times more herbicide in order to inhibit 50% of the enzyme activity, compared to the susceptible biotype. This confirmed a sensitivity modification of the ALS enzyme in the resistant biotypes. The resistant biotypes were less sensitive to the inhibition of the enzyme activity in the presence of the three amino acids. It was possible to conclude that biotype resistance was due to the enzyme insensitivity to iodosulfuron.


2008 ◽  
Vol 22 (4) ◽  
pp. 602-608 ◽  
Author(s):  
Rodrigo Figueroa ◽  
Marlene Gebauer ◽  
Albert Fischer ◽  
Marcelo Kogan

Bensulfuron-methyl (BSM) has been one of the most widely used herbicides in Chilean rice fields because it controls a wide spectrum of weeds and does not require field drainage for application. However, failures of BSM to control water plantain in rice fields have been noted since 2002. We assessed BSM effects on suspected resistant (CU1 and CU2) and susceptible (AN1) water plantain accessions collected in Chilean rice fields during 2004 and 2005. BSM rates resulting in 50% growth reduction (GR50) of CU2 and CU1 plants were 12- and 33-fold higher than for AN1 plants, respectively. Acetolactate synthase (ALS) activity assays in vitro suggested resistance in CU1 and CU2 was due to an ALS enzyme with reduced BSM sensitivity compared to the AN1 biotype. Resistance indices (RI), or ratios of the resistant to susceptibleI50values (BSM rate to inhibit ALS-enzyme activity by 50%), were 266 (CU2/AN1) and > 38,462 (CU1/AN1). This agreed with in vivo ALS activity assays whereRIwere 224 (CU2/AN1) and > 8,533 (CU1/AN1). Resistance levels detected in whole-plant or in vivo ALS activity assays were orders of magnitude lower than those detected in in vitro ALS activity studies suggesting nontarget site mechanisms may have mitigated BSM toxicity. However, a consistent ranking of BSM sensitivity levels (AN1 > CU2 > CU1) throughout all three types of assays suggests resistance is primarily endowed by low target site sensitivity. We conclude that susceptible and resistant water plantain biotypes coexist in Chilean paddies, and the use of integrated weed management involving herbicides with a different mode of action would be imperative to prevent further evolution of resistance to BSM and possibly cross-resistance to other ALS inhibitors. In vitro ALS-enzyme assays provided the best discrimination of resistance levels between biotypes.


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