Japanese Foxtail (Alopecurus japonicus) Resistance to Fenoxaprop and Pinoxaden in China

Weed Science ◽  
2012 ◽  
Vol 60 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Ibrahim A. Mohamed ◽  
Runzhi Li ◽  
Zhenguo You ◽  
Zhaohu Li
Keyword(s):  
Selection Pressure ◽  
Cross Resistance ◽  
Annual Grass ◽  
Site Mutation ◽  
Susceptible Population ◽  
Whole Plant ◽  
The World ◽  
Prior Selection ◽  
Resistant Population ◽  
Evolution Of Resistance

Japanese foxtail is one of the most common and competitive annual grass weeds of wheat in China. Whole-plant dose-response experiments were conducted with fenoxaprop and pinoxaden to confirm and characterize resistant and susceptible Japanese foxtail populations and to elucidate the basis of resistance to these herbicides. The resistant Japanese foxtail population was 49-fold resistant to fenoxaprop and 16-fold (cross) resistant to pinoxaden relative to the susceptible population, which was susceptible to both fenoxaprop and pinoxaden herbicides. Molecular analysis of resistance confirmed that the Ile1781to Leu mutation in the resistant population conferred resistance to both fenoxaprop and pinoxaden. This is the first report of cross resistance of Japanese foxtail to pinoxaden in the world and of a target site mutation that corresponded to resistance to both fenoxaprop and pinoxaden in Japanese foxtail. Prior selection pressure from fenoxaprop could result in evolution of resistance to fenoxaprop and cross resistance to pinoxaden in Japanese foxtail population.

Cross-resistance to acetyl-CoA carboxylase–inhibiting herbicides conferred by a target-site mutation in perennial ryegrass (Lolium perenne) from Argentina

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Marcos Yanniccari ◽  
Ramón Gigón
Keyword(s):  
Seed Production ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Cross Resistance ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Plant Survival ◽  
Winter Cereal ◽  
Susceptible Population ◽  
Resistant Population

AbstractIn Argentina, Lolium spp. occur in 40% of winter cereal crops from the Pampas. Several years ago, cases of glyphosate-resistant perennial ryegrass (Lolium perenne L.) were detected, and the use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides to eradicate these plants has been considered. The aim of this study was to evaluate the sensitivity of a putative pinoxaden-resistant L. perenne population to ACCase-inhibiting herbicides. Around 80% of plants from the putative resistant population survived at a recommended dose of pinoxaden, and they produced viable seeds. The resistance indices (RIs) to pinoxaden were 5.1 and 2.8 for plant survival and seed production, respectively. A single point mutation that conferred a Asp-2078-Gly substitution in ACCase was the source of the resistance. To match the plant control achieved in the susceptible population, the resistant population required 5.4- and 10.4-fold greater doses of clethodim and quizalofop, respectively. RIs for viable seed production when treated with clethodim and quizalofop were 3.3 and 6.6, respectively. The Asp-2078-Gly mutation endowed significant levels of resistance to pinoxaden, clethodim, and quizalofop. For three herbicides, the level of resistance of a pinoxaden-resistant L. perenne population to ACCase inhibitors was evaluated, based on an evaluation of dose response for plant survival and seed production. The RIs were higher for plant survival than for seed production. In Argentina, the selection pressure associated with clethodim and haloxifop preplant application and pinoxaden use on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) crops, would have favored the propagation of the Asp-2078-Gly mutation with its associated resistance.

Target Enzyme-Based Resistance to Clethodim inLolium rigidumPopulations in Australia

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 946-953 ◽  
Author(s):  
Rupinder Kaur Saini ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet Gill
Keyword(s):  
Effective Control ◽  
Cross Resistance ◽  
Single Plant ◽  
Susceptible Population ◽  
Ambient Temperatures ◽  
Resistant Population ◽  
Rigid Ryegrass ◽  
Moderately Resistant ◽  
Two Populations ◽  
Biomass Reduction

Clethodim resistance was identified in 12 rigid ryegrass populations from winter cropping regions in four different states of Australia. Clethodim had failed to provide effective control of these populations in the field and resistance was suspected. Dose–response experiments confirmed resistance to clethodim and butroxydim in all populations. During 2012, the LD50of resistant populations ranged from 10.2 to 89.3 g ha−1, making them 3 to 34–fold more resistant to clethodim than the susceptible population. Similarly, GR50of resistant population varied from 8 to 37.1 g ha−1, which is 3 to 13.9–fold higher than the susceptible population. In 2013, clethodim-resistant populations were 7.8 to 35.3–fold more resistant to clethodim than the susceptible population. The higher resistance factor in 2013, especially in moderately resistant populations, could have been associated with lower ambient temperatures during the winter of 2013. These resistant populations had also evolved cross-resistance to butroxydim. The resistant populations required 1.3 to 6.6–fold higher butroxydim dose to achieve 50% mortality and 3 to 27–fold more butroxydim for 50% biomass reduction compared to the standard susceptible population. Sequencing of the target-site ACCase gene identified five known ACCase substitutions (isoleucine-1781-leucine, isoleucine-2041-asparagine, aspartate-2078-glycine, and cysteine-2088-arginine, and glycine-2096-alanine) in these populations. In nine populations, multiple ACCase mutations were present in different individuals. Furthermore, two alleles with different mutations were present in a single plant of rigid ryegrass in two populations.

Variation in Response and Resistance to Glyphosate and Glufosinate in California Populations of Italian Ryegrass (Lolium perennessp.multiflorum)

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 168-179 ◽  
Author(s):  
Elizabeth Karn ◽  
Roland Beffa ◽  
Marie Jasieniuk
Keyword(s):  
Regression Models ◽  
Early Stage ◽  
Italian Ryegrass ◽  
Cross Resistance ◽  
Susceptible Population ◽  
High Frequencies ◽  
Logistic Regression Models ◽  
Time Period ◽  
Resistant Population ◽  
California Population

Reduced control of Italian ryegrass in California with herbicides has raised concerns about the evolution of populations with resistance to multiple herbicides. The goal of this study was to investigate variation among populations in plant response and resistance to glyphosate and glufosinate in Italian ryegrass from vineyards and orchards in northwest California. Population resistance screening using field-collected seed revealed up to 56.9% of individuals surviving glyphosate treatment at 1,678 g ae ha−1, and 53.5% of individuals surviving glufosinate treatment at 2,242 g ai ha−1in the same population. Frequencies of surviving plants within populations varied among screening times, particularly for glufosinate. Treating vegetatively propagated, genetically identical tillers with each herbicide pointed to separate mechanisms of resistance rather than cross-resistance to glyphosate and glufosinate. Dose–response experiments were conducted for each herbicide at two different screening times using a subset of populations, field-collected seed, and 10 herbicide rates. Plant survival and biomass were evaluated for each population at 3 wk after treatment and for plant regrowth 1 wk thereafter. Log-logistic regression models fit to the data were used to estimate LD50, GR50, and RD50values and calculate resistance indices (R/S ratios). Based on LD50values, the most highly resistant population was 14.4- to 19.2-fold more resistant to glyphosate than the most susceptible population tested but only 1.6- to 2.0-fold more resistant to glufosinate than the most susceptible population tested. Levels of resistance to both herbicides varied with screening time period and variable measured. Results indicate high frequencies of glyphosate-resistant plants but an early stage in the evolution of glufosinate resistance in some Italian ryegrass populations of northwest California.

Target-Site Resistance to Fenoxaprop-P-ethyl in Keng Stiffgrass (Sclerochloa kengiana) from China

Weed Science ◽  
2017 ◽  
Vol 65 (4) ◽  
pp. 452-460 ◽  
Author(s):  
Haitao Gao ◽  
Jiaxing Yu ◽  
Lang Pan ◽  
Xibao Wu ◽  
Liyao Dong
Keyword(s):  
Eastern China ◽  
Point Mutations ◽  
Amino Acid Position ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Resistant Population ◽  
Sequence Method ◽  
Moderate Resistance ◽  
High Level

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.

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.

Patterns of Insecticide Resistance in the Mosquitofish, Gambusia affinis

1969 ◽  
Vol 26 (9) ◽  
pp. 2395-2401 ◽  
Author(s):  
Dudley D. Culley Jr. ◽  
Denzel E. Ferguson
Keyword(s):  
Insecticide Resistance ◽  
High Resistance ◽  
Gambusia Affinis ◽  
Cross Resistance ◽  
Susceptible Population ◽  
State College ◽  
Resistant Population ◽  
Resistance Patterns ◽  
Population Patterns

The extent of insecticide resistance in a resistant population of mosquitofish (Gambusia affinis) from Belzoni, Mississippi, was compared with that of a susceptible population from State College, Mississippi, using 28 insecticides of five major groups. Results of 48-hr bioassays show that resistant mosquitofish have developed high resistance only to the toxaphene–endrin related insecticides, even though insecticides from other groups were heavily applied. Spray records for the Belzoni area and insecticide characteristics such as stability and toxicity aided in evaluating cross-resistance patterns in the resistant population. Patterns of resistance in mosquitofish are similar to those in many resistant arthropods.

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.

Arg-128-Leu target-site mutation in PPO2 evolves in wild poinsettia (Euphorbia heterophylla) with cross-resistance to PPO-inhibiting herbicides

Weed Science ◽  
2020 ◽  
Vol 68 (5) ◽  
pp. 437-444 ◽  
Author(s):  
Rafael R. Mendes ◽  
Hudson K. Takano ◽  
Fernando S. Adegas ◽  
Rubem S. Oliveira ◽  
Todd A. Gaines ◽  
...  
Keyword(s):  
Dose Response ◽  
Ambrosia Artemisiifolia ◽  
Cross Resistance ◽  
Nucleotide Polymorphisms ◽  
Site Mutation ◽  
Metabolic Resistance ◽  
P450 Monooxygenase ◽  
Susceptible Population ◽  
Sites Of Action ◽  
Inhibitor Resistance

AbstractWild poinsettia (Euphorbia heterophylla L.) is a troublesome broadleaf weed in grain production areas in South America. Herbicide resistance to multiple sites of action has been documented in this species, including protoporphyrinogen oxidase (PPO) inhibitors. We investigated the physiological and molecular bases for PPO-inhibitor resistance in a E. heterophylla population (RPPO) from Southern Brazil. Whole-plant dose–response experiments revealed a cross-resistance profile to three different chemical groups of PPO inhibitors. Based on dose–response parameters, RPPO was resistant to lactofen (47.7-fold), saflufenacil (8.6-fold), and pyraflufen-ethyl (3.5-fold). Twenty-four hours after lactofen treatment (120 g ha−1) POST, RPPO accumulated 27 times less protoporphyrin than the susceptible population (SPPO). In addition, RPPO generated 5 and 4.5 times less hydrogen peroxide and superoxide than SPPO, respectively. The chloroplast PPO (PPO1) sequences were identical between the two populations, whereas 35 single-nucleotide polymorphisms were found for the mitochondrial PPO (PPO2). Based on protein homology modeling, the Arg-128-Leu (homologous to Arg-98-Leu in common ragweed [Ambrosia artemisiifolia L.] was the only one located near the catalytic site, also in a conserved region of PPO2. The cytochrome P450 monooxygenase inhibitor malathion did not reverse resistance to lactofen in RPPO, and both populations showed similar levels of PPO1 and PPO2 expression, suggesting that metabolic resistance and PPO overexpression are unlikely. This is the first report of an Arg-128-Leu mutation in PPO2 conferring cross-resistance to PPO inhibitors in E. heterophylla.

Molecular Analysis of Hexazinone-Resistant Shepherd's-Purse (Capsella bursa-pastoris) Reveals a NovelpsbAMutation

Weed Science ◽  
2009 ◽  
Vol 57 (6) ◽  
pp. 574-578 ◽  
Author(s):  
Alejandro Perez-Jones ◽  
Suphannika Intanon ◽  
Carol Mallory-Smith
Keyword(s):  
Point Mutations ◽  
D1 Protein ◽  
Site Directed Mutagenesis ◽  
Gene Encoding ◽  
Ps Ii ◽  
Susceptible Population ◽  
Herbicide Resistant ◽  
Whole Plant ◽  
Alfalfa Field ◽  
Resistant Population

A population of shepherd's-purse suspected to be resistant to the triazinone herbicide hexazinone, a photosystem II (PS II) inhibitor, was collected from an alfalfa field in 2007 in Oregon. A whole-plant, dose–response assay confirmed that the putative-resistant population was highly resistant to hexazinone. The resistant population was 22-fold more resistant to hexazinone than the susceptible population. However, the hexazinone-resistant population was susceptible to other PS II-inhibiting herbicides, including atrazine, diuron, and terbacil. DNA sequence analysis of the chloroplastpsbAgene encoding the D1 protein of PS II, the target site of PS II inhibitors, identified a point mutation from Phe to Ile at position 255 in the hexazinone-resistant population. Single- and double-point mutations at position 255, which is located in the QBbinding niche of the D1 protein, were previously reported inChlamydomonas reinhardtii,Synechococcusspecies, andSynechocystisspecies after site-directed mutagenesis and were associated with decreased binding of PS II inhibitors. To our knowledge, this is the first report of a mutation of thepsbAgene at Phe255in a field-selected, herbicide-resistant plant.

White Skin Privilege: Modern Myth, Forgotten Past

2020 ◽  
Vol 4 (2) ◽  
pp. 63-82
Author(s):  
Peter Frost
Keyword(s):  
Social Relations ◽  
Selection Pressure ◽  
Cross Cultural ◽  
White Slavery ◽  
White Skin ◽  
The Past ◽  
The World ◽  
Cultural Preference ◽  
European Women ◽  
Modern Myth

Abstract European women dominate images of beauty, presumably because Europe has dominated the world for the past few centuries. Yet this presumed cause poorly explains “white slavery”—the commodification of European women for export at a time when their continent was much less dominant. Actually, there has long been a cross-cultural preference for lighter-skinned women, with the notable exception of modern Western culture. This cultural norm mirrors a physical norm: skin sexually differentiates at puberty, becoming fairer in girls, and browner and ruddier in boys. Europeans are also distinguished by a palette of hair and eye colors that likewise differs between the sexes, with women more often having the brighter hues. In general, the European phenotype, especially its brightly colored features, seems to be due to a selection pressure that targeted women, apparently sexual selection. Female beauty is thus a product of social relations, but not solely those of recent times.

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