Target-site resistance to cyhalofop-butyl in bearded sprangletop (Diplachne fusca) from China

Weed Science ◽  
2019 ◽  
Vol 67 (05) ◽  
pp. 534-538 ◽  
Author(s):  
Shuzhong Yuan ◽  
Yingjie Di ◽  
Yueyang Chen ◽  
Yongrui Chen ◽  
Jingxuan Cai ◽  
...  
Keyword(s):  
Amino Acid Position ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Annual Grass ◽  
Site Mutation ◽  
Resistance Level ◽  
First Case ◽  
Resistant Population ◽  
Target Site Resistance ◽  
Grass Weed

AbstractBearded sprangletop [Diplachne fusca(L.) P. Beauv. ex Roem. & Schult. ssp.fascicularis(Lam.) P. M. Peterson & N. Snow] is a noxious annual grass weed of paddy fields, distributed in coastal regions of the Jiangsu and Hebei provinces in China. Cyhalofop-butyl has been widely used to control grass weeds since 2006 in China. Overreliance on cyhalofop-butyl has led to the evolution of resistant weeds. In this study, the resistance level and cyhalofop-butyl resistance mechanisms were investigated in the putative resistant (JSHH) population. The dose–response experiments showed that the JSHHD.fuscapopulation had evolved 8.9-fold resistance to cyhalofop-butyl. Acetyl-CoA carboxylase (ACCase) sequencing revealed a point mutation (GGC to GCC) at amino acid position 2096, resulting in a Gly-2096-Ala substitution in the resistant population. To our knowledge, this is the first case of cyhalofop-butyl resistance inD.fuscaand the first report of a target-site mutation conferring resistance to ACCase-inhibiting herbicides inD.fusca. In addition, the resistantD.fuscapopulation (JSHH) with the Gly-2096-Ala mutation was cross-resistant to the aryloxyphenoxypropionate herbicide metamifop, the cyclohexanedione herbicide sethoxydim, and the phenylpyrazolin herbicide pinoxaden.

scholarly journals Resistance to ACCase inhibitors in Eleusine indica from Brazil involves a target site mutation

2012 ◽  
Vol 30 (3) ◽  
pp. 675-681 ◽  
Author(s):  
M.D. Osuna ◽  
I.C.G.R. Goulart ◽  
R.A. Vidal ◽  
A. Kalsing ◽  
J.P. Ruiz Santaella ◽  
...  
Keyword(s):  
Amino Acid Position ◽  
Target Site ◽  
In Vitro Assays ◽  
Site Mutation ◽  
Eleusine Indica ◽  
Herbicide Resistant ◽  
Frequent Use ◽  
Target Site Resistance ◽  
Grass Weed

Eleusine indica (goosegrass) is a diploid grass weed which has developed resistance to ACCase inhibitors during the last ten years due to the intensive and frequent use of sethoxydim to control grass weeds in soybean crops in Brazil. Plant dose-response assays confirmed the resistant behaviour of one biotype obtaining high resistance factor values: 143 (fenoxaprop), 126 (haloxyfop), 84 (sethoxydim) to 58 (fluazifop). ACCase in vitro assays indicated a target site resistance as the main cause of reduced susceptibility to ACCase inhibitors. PCR-generated fragments of the ACCase CT domain of the resistant and sensitive reference biotype were sequenced and compared. A point mutation was detected within the triplet of aspartate at the amino acid position 2078 (referred to EMBL accession no. AJ310767) and resulted in the triplet of glycine. These results constitute the first report on a target site mutation for a Brazilian herbicide resistant grass weed.

scholarly journals Target-Site Resistance to Glyphosate in Chloris Virgata Biotypes and Alternative Herbicide Options for its Control

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1266
Author(s):  
Het Samir Desai ◽  
Michael Thompson ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Glyphosate Resistance ◽  
Target Site ◽  
Site Mutation ◽  
Glufosinate Ammonium ◽  
Epsps Gene ◽  
First Case ◽  
Target Site Resistance ◽  
Chloris Virgata ◽  
Moderately Resistant ◽  
Dose Response Study

Due to the overdependence on glyphosate to manage weeds in fallow conditions, glyphosate resistance has developed in various biotypes of several grass weeds, including Chloris virgata Sw. The first case of glyphosate resistance in C. virgata was found in 2015 in Australia, and since then several cases have been confirmed in several biotypes across Australia. Pot studies were conducted with 10 biotypes of C. virgata to determine glyphosate resistance levels. The biotypes were identified as either susceptible, moderately resistant or highly resistant based on the glyphosate dose required to kill 50% of plants. Two glyphosate-susceptible (GS) and two glyphosate-resistant (GR) biotypes were identified by the dose-response study and analyzed for the presence of target-site mutation in the 5–enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene. Performance of alternative herbicides to glyphosate as well as the double-knock herbicide approach was evaluated on the two GS (Ch and SGM2) and two GR (SGW2 and CP2) biotypes. Three herbicides, clethodim, haloxyfop and paraquat, were found to be effective (100% control) against all four biotypes when applied at the 4–5 leaf stage. All the sequential herbicide treatments, such as glyphosate followed by paraquat and glufosinate-ammonium followed by paraquat, provided 100% control of all four biotypes of C. virgata. This study identified effective herbicide options for the control of GR C. virgata and showed that target-site mutations were involved in the resistance of two biotypes to glyphosate (SGW2 and CP2). Results could aid farmers in selecting herbicides to manage C. virgata in their fields.

Target-Site Point Mutation Conferring Resistance to Trifluralin in Rigid Ryegrass (Lolium rigidum)

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 246-253 ◽  
Author(s):  
Benjamin Fleet ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet Gill
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Target Site ◽  
Shoot Biomass ◽  
Site Mutation ◽  
Susceptible Population ◽  
Resistant Population ◽  
Target Site Resistance ◽  
Different Populations ◽  
Rigid Ryegrass

Populations of rigid ryegrass suspected of resistance to trifluralin due to control failures exhibited varying levels of susceptibility to trifluralin, with 15 out of 17 populations deemed resistant (>20% plant survival). Detailed dose–response studies were conducted on one highly resistant field-evolved population (SLR74), one known multiply resistant population (SLR31), and one susceptible population (VLR1). On the basis of the dose required to kill 50% of treated plants (LD50), SLR74 had 15-fold greater resistance than VLR1, whereas, the multiply resistant SLR31 had 10-fold greater resistance than VLR1. Similarly, on the basis of dose required to reduce shoot biomass by 50% (GR50), SLR74 had 17-fold greater resistance than VLR1, and SLR31 had 8-fold greater resistance than VLR1. Sequencing of the α-tubulin gene from resistant plants of different populations confirmed the presence of a previously known goosegrass mutation causing an amino acid substitution at position 239 from threonine to isoleucine in resistant population SLR74. This mutation was also found in 4 out of 5 individuals in another highly resistant population TR2 and in 3 out of 5 individuals of TR4. An amino acid substitution from valine to phenylalanine at position 202 was also observed in TR4 (3 out of 5 plants) and TR2 (1 out of 5 plants). There was no target-site mutation identified in SLR31. This study documents the first known case of field-evolved target-site resistance to dinitroaniline herbicides in a population of rigid ryegrass.

Molecular confirmation of resistance to PPO inhibitors in Amaranthus tuberculatus and Amaranthus palmeri, and isolation of the G399A PPO2 substitution in A. palmeri

2020 ◽  
pp. 1-7
Author(s):  
Jacob S. Montgomery ◽  
Darci A. Giacomini ◽  
Patrick J. Tranel
Keyword(s):  
Goodness Of Fit ◽  
Resistance Mechanism ◽  
Amino Acid Position ◽  
Resistance Mechanisms ◽  
Palmer Amaranth ◽  
Target Site ◽  
Coding Region ◽  
Common Waterhemp ◽  
Growing Seasons ◽  
Target Site Resistance

Abstract During the 2017 to 2019 growing seasons, samples of waterhemp and Palmer amaranth that had reportedly survived field-rate applications of protoporphyrinogen oxidase (PPO)–inhibiting herbicides were collected from the American Midwest and tested for target-site mutations known at the time to confer resistance. Target-site resistance was identified in nearly all (135 of 145) tested common waterhemp populations but in only 8 of 13 Palmer amaranth populations. Follow-up research on one population of Palmer amaranth (W-8), which tested negative for all such mutations, confirmed it was resistant to lactofen, with a magnitude of resistance comparable to that conferred by the ΔG210 PPO2 mutation. Gene sequences from both isoforms of PPO (PPO1 and PPO2) were compared between W-8 and known PPO inhibitor–sensitive sequence. A glycine-to-alanine substitution at the 399th amino acid position (G399A) of PPO2, recently identified to reduce target-site herbicide sensitivity, was observed in a subset of resistant W-8 plants. Because no missense mutation completely delimited resistant and sensitive sequences, we initially suspected the presence of a secondary, non-target-site resistance mechanism in this population. To isolate G399A, a segregating F2 population was produced and screened with a delimiting rate of lactofen. χ2 goodness-of-fit analysis of dead/alive ratings indicated single-locus inheritance of resistance in the F2 population, and molecular markers for the W-8 parental PPO2 coding region co-segregated tightly, but not perfectly, with resistance. More research is needed to fully characterize Palmer amaranth PPO inhibitor–resistance mechanisms, which appear to be more diverse than those found in common waterhemp.

scholarly journals Non-Target Site Mechanisms Endow Resistance to Glyphosate in Saltmarsh Aster (Aster squamatus)

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1970
Author(s):  
José Alfredo Domínguez-Valenzuela ◽  
Ricardo Alcántara-de la Cruz ◽  
Candelario Palma-Bautista ◽  
José Guadalupe Vázquez-García ◽  
Hugo E. Cruz-Hipolito ◽  
...  
Keyword(s):  
Shikimic Acid ◽  
Glyphosate Resistance ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Weed Species ◽  
The Third ◽  
Citrus Groves ◽  
First Case ◽  
Treated Leaf ◽  
Target Site Resistance

Of the six-glyphosate resistant weed species reported in Mexico, five were found in citrus groves. Here, the glyphosate susceptibility level and resistance mechanisms were evaluated in saltmarsh aster (Aster squamatus), a weed that also occurs in Mexican citrus groves. The R population accumulated 4.5-fold less shikimic acid than S population. S plants hardly survived at 125 g ae ha−1 while most of the R plants that were treated with 1000 g ae ha−1, which suffered a strong growth arrest, showed a vigorous regrowth from the third week after treatment. Further, 5-enolpyruvylshikimate-3-phosphate basal and enzymatic activities did not diverge between populations, suggesting the absence of target-site resistance mechanisms. At 96 h after treatment, R plants absorbed ~18% less glyphosate and maintained 63% of the 14C-glyphsoate absorbed in the treated leaf in comparison to S plants. R plants metabolized twice as much (72%) glyphosate to amino methyl phosphonic acid and glyoxylate as the S plants. Three non-target mechanisms, reduced absorption and translocation and increased metabolism, confer glyphosate resistance saltmarsh aster. This is the first case of glyphosate resistance recorded for A. squamatus in the world.

Importance of the P106S Target-Site Mutation in Conferring Resistance to Glyphosate in a Goosegrass (Eleusine indica) Population from the Philippines

Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Shiv S. Kaundun ◽  
Ian A. Zelaya ◽  
Richard P. Dale ◽  
Amy J. Lycett ◽  
Patrice Carter ◽  
...  
Keyword(s):  
Pcr Amplification ◽  
Resistance Mechanisms ◽  
The Philippines ◽  
Target Site ◽  
Growth Stages ◽  
Site Mutation ◽  
Resistance Level ◽  
Report Data ◽  
Polymerase Chain ◽  
Moderate Resistance

Few studies on herbicide resistance report data to establish unambiguously the correlation between genotype and phenotype. Here we report on the importance of the EPSPS prolyl106point mutation to serine (P106S) in conferring resistance to glyphosate in a goosegrass population from Davao, Mindanao Island, the Philippines (Davao). Initial rate-response studies showed clear survivors within the Davao population at glyphosate rates that completely controlled the standard sensitive goosegrass population (STD1). Assessment of potential resistance mechanisms identified the presence of P106S mutant individuals in the Davao population. Polymerase chain reaction (PCR) amplification of specific alleles (PASA) analysis established that the mixed-resistant Davao population was comprised of 39.1% homozygous proline wild-type (PP106), 3.3% heterozygous serine mutant (PS106), and 57.6% homozygous serine mutant (SS106) genotypes. Further rate-response studies on plants with a predetermined genotype estimated the Davao SS106 individuals to be approximately 2-fold more resistant to glyphosate compared to Davao PP106 individuals. Extensive analysis at different goosegrass growth stages and glyphosate rates established strong correlation (P < 0.001) between presence of P106S in EPSPS and the resistant phenotype. Importantly, no differences in the pattern of absorbed or translocated14C–glyphosate were observed between PP106 and SS106 Davao genotypes or Davao and STD1 individuals, suggesting that glyphosate resistance in the Davao population was attributable to an altered target site mechanism. This study demonstrates that whilst P106S in EPSPS confers a moderate resistance level to glyphosate, the mechanism is sufficient to endow glyphosate failure at the recommended field rates.

Functional Genomics Analysis of Horseweed (Conyza canadensis) with Special Reference to the Evolution of Non–Target-Site Glyphosate Resistance

Weed Science ◽  
2010 ◽  
Vol 58 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Joshua S. Yuan ◽  
Laura L. G. Abercrombie ◽  
Yongwei Cao ◽  
Matthew D. Halfhill ◽  
Xin Zhou ◽  
...  
Keyword(s):  
Functional Genomics ◽  
Molecular Mechanisms ◽  
Glyphosate Resistance ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Environmentally Benign ◽  
Conyza Canadensis ◽  
Target Site Resistance ◽  
Weedy Species ◽  
Heterologous Microarray

The evolution of glyphosate resistance in weedy species places an environmentally benign herbicide in peril. The first report of a dicot plant with evolved glyphosate resistance was horseweed, which occurred in 2001. Since then, several species have evolved glyphosate resistance and genomic information about nontarget resistance mechanisms in any of them ranges from none to little. Here, we report a study combining iGentifier transcriptome analysis, cDNA sequencing, and a heterologous microarray analysis to explore potential molecular and transcriptomic mechanisms of nontarget glyphosate resistance of horseweed. The results indicate that similar molecular mechanisms might exist for nontarget herbicide resistance across multiple resistant plants from different locations, even though resistance among these resistant plants likely evolved independently and available evidence suggests resistance has evolved at least four separate times. In addition, both the microarray and sequence analyses identified non–target-site resistance candidate genes for follow-on functional genomics analysis.

Target and Non–target site Mechanisms Confer Resistance to Glyphosate in Canadian Accessions ofConyza canadensis

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 234-245 ◽  
Author(s):  
Eric R. Page ◽  
Christopher M. Grainger ◽  
Martin Laforest ◽  
Robert E. Nurse ◽  
Istvan Rajcan ◽  
...  
Keyword(s):  
Ssr Markers ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Conyza Canadensis ◽  
Weed Species ◽  
Target Site Resistance ◽  
Selection For ◽  
Simple Sequence ◽  
Growing Region ◽  
Selection Of

Glyphosate-resistant populations ofConyza canadensishave been spreading at a rapid rate in Ontario, Canada, since first being documented in 2010. Determining the genetic relationship among existing Ontario populations is necessary to understand the spread and selection of the resistant biotypes. The objectives of this study were to: (1) characterize the genetic variation ofC. canadensisaccessions from the province of Ontario using simple sequence repeat (SSR) markers and (2) investigate the molecular mechanism (s) conferring resistance in these accessions. Ninety-eightC. canadensisaccessions were genotyped using 8 SSR markers. Germinable accessions were challenged with glyphosate to determine their dose response, and the sequences of 5-enolpyruvylshikimate-3-phosphate synthase genes 1 and 2 were obtained. Results indicate that a majority of glyphosate-resistant accessions from Ontario possessed a proline to serine substitution at position 106, which has previously been reported to confer glyphosate resistance in other crop and weed species. Accessions possessing this substitution demonstrated notably higher levels of resistance than non–target site resistant (NTSR) accessions from within or outside the growing region and were observed to form a subpopulation genetically distinct from geographically proximate glyphosate-susceptible and NTSR accessions. Although it is unclear whether other non–target site resistance mechanisms are contributing to the levels of resistance observed in target-site resistant accessions, these results indicate that, at a minimum, selection for Pro-106-Ser has occurred in addition to selection for non–target site resistance and has significantly enhanced the levels of resistance to glyphosate inC. canadensisaccessions from Ontario.

Confirmation and characterization of cyhalofop-butyl–resistant Chinese sprangletop (Leptochloa chinensis) populations from China

Weed Science ◽  
2020 ◽  
Vol 68 (3) ◽  
pp. 253-259
Author(s):  
Yajun Peng ◽  
Lang Pan ◽  
Ducai Liu ◽  
Xiaomei Cheng ◽  
Guolan Ma ◽  
...  
Keyword(s):  
Resistance Index ◽  
Resistance Mechanisms ◽  
The Other ◽  
Susceptible Population ◽  
Acetyl Coenzyme A ◽  
Target Site Resistance ◽  
High Level ◽  
Acetyl Coenzyme A Carboxylase ◽  
Grass Weed

AbstractChinese sprangletop [Leptochloa chinensis (L.) Nees] is one grass weed severely affecting rice (Oryza sativa L.) growth in paddies in China. Cyhalofop-butyl is the main herbicide used to control grass weeds in Chinese paddy fields, especially for controlling L. chinensis; however, L. chinensis has evolved resistance to cyhalofop-butyl due to continuous and extensive application. To investigate cyhalofop-butyl resistance levels and mechanisms in L. chinensis in some of the Chinese rice areas, 66 field populations were collected and treated with cyhalofop-butyl. Of these tested populations, 10 showed a high level of resistance to cyhalofop-butyl; the 50% effective dose ranged within 108.4 to 1,443.5 g ai ha−1 with resistance index values of 9.1 to 121.8 when compared with the susceptible population. Acetyl-coenzyme A carboxylase genes (ACCase) of susceptible and all 10 resistant populations were amplified and sequenced. Among them, Ile-1781-Leu, Trp-2027-Cys, Trp-2027-Ser, and Ile-2041-Asn mutations were found in five resistant populations. No known resistance-related mutations were found in the other five resistant populations, indicating that resistance to cyhalofop-butyl in these populations was likely to be endowed by non–target site resistance mechanisms. Notably, the Ile-1781-Leu and Trp-2027-Cys substitutions have previously been reported, but this is the first report of Trp-2027-Ser and Ile-2041-Asn mutations in L. chinensis. Furthermore, three derived cleaved amplified polymorphic sequence methods were developed to rapidly detect these mutations in L. chinensis.

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