scholarly journals Non-Target-Site Resistance to Herbicides: Recent Developments

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 417 ◽  
Author(s):  
Jugulam ◽  
Shyam
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Target Site ◽  
Cross Resistance ◽  
Weed Species ◽  
Physiological Processes ◽  
Recent Developments ◽  
Target Site Resistance ◽  
Resistance To Herbicides ◽  
Selection Of

Non-target-site resistance (NTSR) to herbicides in weeds can be conferred as a result of the alteration of one or more physiological processes, including herbicide absorption, translocation, sequestration, and metabolism. The mechanisms of NTSR are generally more complex to decipher than target-site resistance (TSR) and can impart cross-resistance to herbicides with different modes of action. Metabolism-based NTSR has been reported in many agriculturally important weeds, although reduced translocation and sequestration of herbicides has also been found in some weeds. This review focuses on summarizing the recent advances in our understanding of the physiological, biochemical, and molecular basis of NTSR mechanisms found in weed species. Further, the importance of examining the co-existence of TSR and NTSR for the same herbicide in the same weed species and influence of environmental conditions in the altering and selection of NTSR is also discussed. Knowledge of the prevalence of NTSR mechanisms and co-existing TSR and NTSR in weeds is crucial for designing sustainable weed management strategies to discourage the further evolution and selection of herbicide resistance in weeds.

Decoding Non-Target-Site Herbicide Resistance in Sunflower: The Beginning of the Story

Helia ◽  
2019 ◽  
Vol 42 (70) ◽  
pp. 1-16
Author(s):  
Mercedes Gil ◽  
Graciela Nestares
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Weed Management ◽  
Management Strategies ◽  
Target Site ◽  
Acetohydroxyacid Synthase ◽  
Cross Resistance ◽  
Resistance To Herbicides ◽  
Transgenic Technologies ◽  
New Compounds

AbstractIn the last years, many efforts have been made to develop sunflower cultivars showing important agronomical characteristics such as herbicide resistance. These approaches have been focused mainly on resistance to herbicides with the same mode of action, that is acetohydroxyacid synthase (AHAS) inhibitors. To date, four induced and natural AHAS mutations have been found that confer resistance to these herbicides and many of these alleles are being used for the production of sunflower hybrids resistant to herbicides and to develop different non-transgenic technologies for weed control. However, little is known about the bases of non-target-site-based resistance (NTSR) developing cross-resistance to herbicides with different modes of action in sunflower. These mechanisms diminish the number of active herbicide molecules that reach the target and are generally polygenic. Elucidating the nature of NTSR would allow evaluating maximal efficiency conditions for the herbicide and would enable to establish weed management strategies in sunflower crop. Nowadays, mining of NTSR genes can be more easily accomplished taking advantage of up-to-date omics-based approaches: high-throughput techniques involving genomics, transcriptomics, proteomics and metabolomics. Considering the difficulties in the discovery of new compounds with a broad spectrum of weed control, it results essential to broaden the use of former herbicides which are highly efficient and ecologically desirable. Full understanding of NTSR mechanisms in sunflower would allow detecting specific genes potentially useful as biotechnological tools for the phytoremediation of herbicides and modern plant breeding.

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.

Widespread herbicide resistance in pigweed species in Ontario carrot production is due to multiple photosystem II mutations

2020 ◽  
Vol 100 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Gareth Davis ◽  
Jocelyne Letarte ◽  
Christopher M. Grainger ◽  
Istvan Rajcan ◽  
François J. Tardif
Keyword(s):  
Photosystem Ii ◽  
Weed Management ◽  
Continuous Selection ◽  
Amaranthus Retroflexus ◽  
Cross Resistance ◽  
Single Mutation ◽  
Weed Species ◽  
Double Mutation ◽  
First Report ◽  
Selection Of

The apparent efficacy of linuron to control pigweeds (Amaranthus spp.) has declined in Ontario, Canada, in past decades, possibly due to resistance. Samples were collected in multiple fields across Ontario with reported linuron failure. These were characterized at the whole-plant and molecular levels. Screening with linuron revealed resistance in six out of nine green pigweed (Amaranthus powellii Wats.) populations and 36 out of 38 populations of redroot pigweed (Amaranthus retroflexus L.). Sequencing of the psbA gene showed resistant plants had mutations conferring resistance to photosystem II (PSII) inhibitors. The most commonly seen mutation was coding for a Val219Ile substitution, while other populations had Ala251Val or Phe274Val. Two populations were documented with a double mutation at Val219Ile and Phe274Val. All substitutions endowed plants with low to moderate resistance to linuron, with various levels of cross resistance to other PSII inhibitors. The double mutants were characterized by higher levels of resistance to linuron and diuron compared with each single substitution. The widespread failure of linuron to control pigweed species in many carrot fields in Ontario is due to the selection of PSII mutants. This is the first report of double mutation in psbA in any weed species and the first report of Ala251Val and Phe273Val in pigweed species. The presence of a double mutation is probably the result of continuous selection of plants already resistant due to a single mutation. Our results illustrate the need for diversified weed management strategies in crops where herbicide options are limited.

scholarly journals Point Mutations and Cytochrome P450 Can Contribute to Resistance to ACCase-Inhibiting Herbicides in Three Phalaris Species

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1703
Author(s):  
José G. Vázquez-García ◽  
Joel Torra ◽  
Candelario Palma-Bautista ◽  
Ricardo Alcántara-de la Cruz ◽  
Rafael De Prado
Keyword(s):  
Point Mutations ◽  
Resistance Mechanisms ◽  
Target Site ◽  
In Vitro Assays ◽  
Cross Resistance ◽  
Northern Iran ◽  
Target Site Resistance ◽  
Acetyl Coenzyme A Carboxylase ◽  
Selection Of

Species of Phalaris have historically been controlled by acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides; however, overreliance on herbicides with this mechanism of action has resulted in the selection of resistant biotypes. The resistance to ACCase-inhibiting herbicides was characterized in Phalaris brachystachys, Phalaris minor, and Phalaris paradoxa samples collected from winter wheat fields in northern Iran. Three resistant (R) biotypes, one of each Phalaris species, presented high cross-resistance levels to diclofop-methyl, cycloxydim, and pinoxaden, which belong to the chemical families of aryloxyphenoxypropionates (FOPs), cyclohexanediones (DIMs), and phenylpyrazolines (DENs), respectively. The metabolism of 14C-diclofop-methyl contributed to the resistance of the P. brachystachys R biotype, while no evidence of herbicide metabolism was found in P. minor or P. paradoxa. ACCase in vitro assays showed that the target sites were very sensitive to FOP, DIM, and DEN herbicides in the S biotypes of the three species, while the R Phalaris spp. biotypes presented different levels of resistance to these herbicides. ACCase gene sequencing confirmed that cross-resistance in Phalaris species was conferred by specific point mutations. Resistance in the P. brachystachys R biotype was due to target site and non-target-site resistance mechanisms, while in P. minor and P. paradoxa, only an altered target site was found.

Cross Resistance to Diquat in Glyphosate/Paraquat-Resistant Conyza bonariensis and Conyza canadensis and Confirmation of 2,4-D Resistance in Conyza bonariensis

2021 ◽  
pp. 1-22
Author(s):  
Marcelo L. Moretti ◽  
Lucas K. Bobadilla ◽  
Bradley D. Hanson
Keyword(s):  
Management Strategies ◽  
Resistance Management ◽  
Cross Resistance ◽  
Similar Response ◽  
Weed Species ◽  
Conyza Bonariensis ◽  
Whole Plant ◽  
Site Of Action ◽  
Target Site Resistance ◽  
Sites Of Action

Abstract Hairy fleabane and horseweed are pervasive weed species in agriculture. Glyphosate-resistant (GR) and glyphosate-paraquat-resistant (GPR) biotypes challenge current management strategies. These GR and GPR biotypes have non-target-site-resistance (NTSR), which can confer resistance to herbicides with different sites of action. This study’s objective was to characterize the response of GR, GPR, and glyphosate-paraquat-susceptible (GPS) biotypes of both Conyza spp. to herbicides with a different site of action. Whole-plant dose-response bioassays indicated a similar response among tested biotypes of both Conyza spp. to rimsulfuron, dicamba, hexazinone, glufosinate, flumioxazin, saflufenacil, or mesotrione. The C. bonariensis GR and GPR biotypes were 2.7- and 2.9-fold resistant to 2,4-D relative to the GPS biotype (GR50 766.7 g ai ha-1), confirming 2,4-D resistance in C. bonariensis for the first time in California. The GR and GPR biotypes were not cross-resistant to dicamba. No differences in response to 2,4-D were observed among C. canadensis biotypes with a GR50 ranging from 150.2 to 277.4 g ai ha-1. The GPR biotypes of both species were cross-resistant to diquat with a 44.0-fold resistance in C. bonariensis (GR50 863.7 g ai ha-1) and 15.6-fold resistance in C. canadensis (GR50 563.1 g ai ha-1). The confirmation of multiple resistances to glyphosate, paraquat, and 2,4-D in C. bonariensis curtails herbicide site of action alternatives and jeopardizes resistance management strategies based on herbicide rotation and tank-mixtures, underscoring the critical need for non-chemical weed control alternatives.

scholarly journals Weed resistance to herbicides

2020 ◽  
Vol 29 (2) ◽  
pp. 79-96
Author(s):  
Sava Vrbničanin
Keyword(s):  
Herbicide Resistance ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Target Site ◽  
Weed Species ◽  
Ps Ii ◽  
Target Site Resistance ◽  
Resistance To Herbicides ◽  
Als Inhibitors ◽  
Weed Resistance

Weed resistance to herbicides represents the acquired resistance of individuals to complete the life cycle and leave offspring in the conditions of extended exposure to the same herbicide, i.e. herbicides of the same mechanism of action to which they were sensitive at the beginning of the application. Based on the herbicide resistance mechanisms, all processes can be grouped as follows: target-site resistance, non-target-site resistance, cross-resistance and multiple-resistance. Currently, herbicide resistance has been reported in 514 cases (species x site of action) worldwide, in 262 weed species (152 dicotyledons, 110 monocotyledons). Many of those biotypes are resistant to als inhibitors, PS II inhibitors, EPSPS inhibitors and ACC-ase inhibitors. The higher degree of resistance to als inhibitors has been confirmed in the following weed species: Amaranthus retroflexus, Sorghum halepense, Ambrosia artemisiifolia and Helianthus annuus.

WeedSOFT®: a weed management decision support system

Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Christophe Neeser ◽  
J. Anita Dille ◽  
Gopal Krishnan ◽  
David A. Mortensen ◽  
Jeffery T. Rawlinson ◽  
...  
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Weed Management ◽  
Management Strategies ◽  
Maximum Yield ◽  
Management Decision ◽  
Weed Species ◽  
Line Drawings ◽  
Selection Of

WeedSOFT® is a decision support system that was developed to help farmers and consultants in Nebraska with the selection of optimal weed management strategies. WeedSOFT® evolved from HERB, a bioeconomic model for soybean that was developed in North Carolina. The program is composed of four independent modules, namely, ADVISOR, EnviroFX, MapVIEW, and WeedVIEW. ADVISOR helps the user select a treatment based on maximum yield or maximum net gain. EnviroFX and MapVIEW provide environmentally relevant herbicide information and county soil maps that indicate vulnerability to groundwater contamination. WeedVIEW is a visual library of color images and line drawings of 46 common weed species. Over 500 farmers and consultants in Nebraska and adjacent states use WeedSOFT®. As a result of the current regionalization effort, the user base is expected to increase rapidly during the next 2 or 3 yr. This article explains the algorithms implemented in the current version of WeedSOFT®.

scholarly journals Interactions of Nitrogen Source and Rate and Weed Removal Timing Relative to Nitrogen Content in Corn and Weeds and Corn Grain Yield

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Alexandra M. Knight ◽  
Wesley J. Everman ◽  
David L. Jordan ◽  
Ronnie W. Heiniger ◽  
T. Jot Smyth
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Management Strategies ◽  
Field Studies ◽  
Weed Species ◽  
Weed Interference ◽  
Coated Urea ◽  
N Fertility ◽  
Corn Grain ◽  
Corn Grain Yield

Adequate fertility combined with effective weed management is important in maximizing corn (Zea mays L.) grain yield. Corn uptake of nitrogen (N) is dependent upon many factors including weed species and density and the rate and formulation of applied N fertilizer. Understanding interactions among corn, applied N, and weeds is important in developing management strategies. Field studies were conducted in North Carolina to compare corn and weed responses to urea ammonium nitrate (UAN), sulfur-coated urea (SCU), and composted poultry litter (CPL) when a mixture of Palmer amaranth (Amaranthus palmeri S. Wats.) and large crabgrass (Digitaria sanguinalis L.) was removed with herbicides at heights of 8 or 16 cm. These respective removal timings corresponded with 22 and 28 days after corn planting or V2 and V3 stages of growth, respectively. Differences in N content in above-ground biomass of corn were noted early in the season due to weed interference but did not translate into differences in corn grain yield. Interactions of N source and N rate were noted for corn grain yield but these factors did not interact with timing of weed control. These results underscore that timely implementation of control tactics regardless of N fertility management is important to protect corn grain yield.

Model of rice (Oryza sativa) yield reduction as a function of weed interference

Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Karl W. VanDevender ◽  
Thomas A. Costello ◽  
Roy J. Smith
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Economic Assessment ◽  
Richards Equation ◽  
Yield Reduction ◽  
Published Data ◽  
Weed Species ◽  
Individual Parameter ◽  
Alternative Weed Control ◽  
Parameter Values

Economic assessment of weed management strategies in rice is dependent upon a quantitative estimate of the yield impact of a given weed population. To assist rice producers in making such assessments, a mathematical model was developed to predict rice yield reduction as a function of weed density and duration of interference. The nonlinear empirical model was a unique 3-dimensional adaptation of the Richards equation with 4 parameters. Using published data, individual parameter values were fitted for each of 6 weed species interfering with either conventional or semi-dwarf statured rice cultivars. The functional form of the equation produced surfaces that were qualitatively consistent with available data and experience regarding rice-weed biology. Hence, predictions from the model should be useful and reliable in assessing the economic impact of weeds and in determining the feasibility of alternative weed control treatments for various field scenarios.

scholarly journals Floristic and Phytosociology of Weeds in Upland Rice in the Humid Tropics

2018 ◽  
Vol 35 (0) ◽  
Author(s):  
M.R.M. SILVA ◽  
E.A. COSTA ◽  
M.J.P. CORRÊA ◽  
A.A.C. RODRIGUES ◽  
M.L.R. MESQUITA
Keyword(s):  
Weed Management ◽  
Upland Rice ◽  
Management Strategies ◽  
Floristic Composition ◽  
Humid Tropics ◽  
Reproductive Stage ◽  
Rice Crop ◽  
Weed Species ◽  
Floristic Similarity ◽  
Abstract Knowledge

ABSTRACT: Knowledge of the floristic composition and vegetation structure are essential conditions for development of more efficient and economic weed management strategies in crops in the humid tropics. The objective of the research was to carry on floristic and phytosociological surveys to know the main weeds in upland rice fields in the humid tropics of the Brazilian State of Maranhão. Weed samples were done by means of an open metal rectangle of 0.15 m2 thrown at random in the vegetative and reproductive stages of rice crop in 2009/10 and 2010/2011 harvest. A total of 65 species from 23 families was identified 35 (53.85%) from the eudicotyledons botanical group, 29 (44.06%) from the monocotyledonous and one (1.53%) belonged to the pteridophytes. The most representative families were from the monocotyledonous botanical group including Poaceae and Cyperaceae, followed by Amaranthaceae and Malvaceae, both from the eudicotyledons group. The weed species with higher importance values in the upland rice crop vegetative stage were Urochloasp., Panicumsp., C. flavus, C. benghalensis and C. argutus whereas in the reproductive stage the higher importance values were recorded for S. latifolia, C. argutus, L. octovalvis, A.tenella and P.maximum. The most important weeds in the crop vegetative phase were mainly from the monocotyledonous group, while in reproductive one they were the eudicotyledons. Weed diversity was high and the floristic similarity was lower in the vegetative one compared to the reproductive stage of upland rice cultivation in the humid tropics.

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