A dinitroaniline herbicide resistance mutation can be nearly lethal to plants

2022 ◽  
Author(s):  
Yanhui Wang ◽  
Heping Han ◽  
Jinyi Chen ◽  
Qin Yu ◽  
Martin Vila‐Aiub ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Resistance Mutation

scholarly journals Unravelling the effect of two herbicide resistance mutations on acetolactate synthase kinetics and growth traits

2020 ◽  
Vol 71 (12) ◽  
pp. 3535-3542
Author(s):  
Ning Zhao ◽  
Yanyan Yan ◽  
Long Du ◽  
Xiaolin Zhang ◽  
Weitang Liu ◽  
...  
Keyword(s):  
Plant Growth ◽  
Herbicide Resistance ◽  
Evolutionary Dynamics ◽  
Growth Traits ◽  
Resistance Mutation ◽  
Acetolactate Synthase ◽  
Pleiotropic Effects ◽  
Substrate Affinity ◽  
Common Mutation ◽  
Resistance Mutations

Abstract Gene mutations conferring herbicide resistance are hypothesized to have negative pleiotropic effects on plant growth and fitness, which may in turn determine the evolutionary dynamics of herbicide resistance alleles. We used the widespread, annual, diploid grass weed Alopecurus aequalis as a model species to investigate the effect of two resistance mutations—the rare Pro-197-Tyr mutation and the most common mutation, Trp-574-Leu—on acetolactate synthase (ALS) functionality and plant growth. We characterized the enzyme kinetics of ALS from two purified A. aequalis populations, each homozygous for the resistance mutation 197-Tyr or 574-Leu, and assessed the pleiotropic effects of these mutations on plant growth. Both mutations reduced sensitivity of ALS to ALS-inhibiting herbicides without significant changes in extractable ALS activity. The 197-Tyr mutation slightly decreased the substrate affinity (corresponding to an increased Km for pyruvate) and maximum reaction velocity (Vmax) of ALS, whereas the 574-Leu mutation significantly increased these kinetics. Significant decrease or increase in plant growth associated, respectively, with the 197-Tyr and 574-Leu resistance mutations was highly correlated with their impact on ALS kinetics, suggesting more likely persistence of the 574-Leu mutation than the 197-Tyr mutation if herbicide application is discontinued.

An isoleucine to leucine mutation in acetyl-CoA carboxylase confers herbicide resistance in wild oat

Genome ◽  
2002 ◽  
Vol 45 (6) ◽  
pp. 1049-1056 ◽  
Author(s):  
Michael J Christoffers ◽  
Michelle L Berg ◽  
Calvin G Messersmith
Keyword(s):  
Herbicide Resistance ◽  
Dna Sequences ◽  
Resistance Mutation ◽  
Triticum Aestivum L ◽  
Wild Oat ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Herbicide Resistant ◽  
Binding Domains ◽  
Substitution Site

Wild oat (Avena fatua L.) populations resistant to herbicides that inhibit acetyl-CoA carboxylase (ACCase; EC 6.4.1.2) represent an increasingly important weed control problem. The objective of this study was to determine the ACCase mutation responsible for herbicide resistance in a well-studied wild oat biotype (UM1). A 2039-bp region encompassing the carboxybiotin and acetyl-CoA binding domains of multifunctional plastidic ACCase was analyzed. DNA sequences representing three plastidic ACCase gene loci were isolated from both the resistant UM1 and a herbicide-susceptible biotype, consistent with the hexaploid nature of wild oat. Only one nonsynonymous point mutation was found among the resistant wild oat sequences, inferring an isoleucine to leucine substitution. The position of this substitution corresponds to residue 1769 of wheat (Triticum aestivum L.) plastidic ACCase (GenBank accession No. AF029895). Analysis of an F2 population derived from a cross between a herbicide-resistant and a susceptible biotype confirmed co-segregation of herbicide resistance with the mutated ACCase. We conclude that the isoleucine to leucine mutation is responsible for herbicide resistance in UM1 wild oat based on a comparison of the substitution site across species and ACCase types. While isoleucine is conserved among plastidic ACCases of herbicide-susceptible grasses, leucine is found in plastidic and cytosolic forms of multifunctional herbicide-resistant ACCase.Key words: acetyl-CoA carboxylase, herbicide resistance, mutation, wild oat.

New Technologies to Combat Herbicide Resistance

2020 ◽  
Vol 31 (2) ◽  
pp. 90-92
Author(s):  
Rob Edwards
Keyword(s):  
Winter Wheat ◽  
Herbicide Resistance ◽  
Cover Crops ◽  
New Technologies ◽  
Green Revolution ◽  
Arable Land ◽  
Limited Range ◽  
Cultural Control ◽  
Arable Farming ◽  
The Uk

Herbicide resistance in problem weeds is now a major threat to global food production, being particularly widespread in wild grasses affecting cereal crops. In the UK, black-grass (Alopecurus myosuroides) holds the title of number one agronomic problem in winter wheat, with the loss of production associated with herbicide resistance now estimated to cost the farming sector at least £0.5 billion p.a. Black-grass presents us with many of the characteristic traits of a problem weed; being highly competitive, genetically diverse and obligately out-crossing, with a growth habit that matches winter wheat. With the UK’s limited arable crop rotations and the reliance on the repeated use of a very limited range of selective herbicides we have been continuously performing a classic Darwinian selection for resistance traits in weeds that possess great genetic diversity and plasticity in their growth habits. The result has been inevitable; the steady rise of herbicide resistance across the UK, which now affects over 2.1 million hectares of some of our best arable land. Once the resistance genie is out of the bottle, it has proven difficult to prevent its establishment and spread. With the selective herbicide option being no longer effective, the options are to revert to cultural control; changing rotations and cover crops, manual rogueing of weeds, deep ploughing and chemical mulching with total herbicides such as glyphosate. While new precision weeding technologies are being developed, their cost and scalability in arable farming remains unproven. As an agricultural scientist who has spent a working lifetime researching selective weed control, we seem to be giving up on a technology that has been a foundation stone of the green revolution. For me it begs the question, are we really unable to use modern chemical and biological technology to counter resistance? I would argue the answer to that question is most patently no; solutions are around the corner if we choose to develop them.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

scholarly journals Detection of EGFR Activating and Resistance Mutations by Droplet Digital PCR in Sputum of EGFR-Mutated NSCLC Patients

2021 ◽  
Vol 15 ◽  
pp. 117955492199307
Author(s):  
Klaus Hackner ◽  
Anna Buder ◽  
Maximilian J Hochmair ◽  
Matthaeus Strieder ◽  
Christina Grech ◽  
...  
Keyword(s):  
Stable Disease ◽  
Progressive Disease ◽  
Kinase Inhibitor ◽  
Diagnostic Yield ◽  
Resistance Mutation ◽  
Egfr Mutations ◽  
Plasma Samples ◽  
Percent Agreement ◽  
Nsclc Patients ◽  
Egfr Mutated

Background: Proof of the T790M resistance mutation is mandatory if patients with EGFR-mutated non-small cell lung cancer (NSCLC) progress under first- or second-generation tyrosine kinase inhibitor therapy. In addition to rebiopsy, analysis of plasma circulating tumor DNA is used to detect T790M resistance mutation. We studied whether sputum is another feasible specimen for detection of EGFR mutations. Methods: Twenty-eight patients with advanced EGFR-mutated NSCLC were included during stable and/or progressive disease. The initial activating EGFR mutations (exon 19 deletions or L858R mutations) at stable disease and at progressive disease (together with T790M) were assessed in simultaneously collected plasma and sputum samples and detected by droplet digital polymerase chain reaction (ddPCR). Results: Activating EGFR mutations were detected in 47% of the plasma samples and 41% of sputum samples during stable disease, and in 57% of plasma samples and 64% of sputum samples during progressive disease. T790M was detected in 44% of the plasma samples and 66% of the sputum samples at progressive disease. In ddPCR T790M-negative results for both specimens (plasma and sputum), negativity was confirmed by rebiopsy in 5 samples. Concordance rate of plasma and sputum for T790M was 0.86, with a positive percent agreement of 1.0 and a negative percent agreement of 0.80. Conclusions: We demonstrated that EGFR mutation analysis with ddPCR is feasible in sputum samples. Combination of plasma and sputum analyses for detection of T790M in NSCLC patients with progressive disease increases the diagnostic yield compared with molecular plasma analysis alone.

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