Widespread occurrence of both metabolic and target-site herbicide resistance mechanisms inLolium rigidumpopulations

Alopecurus myosuroides and Lolium rigidum have developed resistance to herbicides with several modes of action in many herbicide classes. A. myosuroides biotype Peldon A1 from England exhibits non-target site cross resistance to substituted urea and aryloxyphenoxypropionate herbicides (APP) due to enhanced metabolism. L. rigidum biotype SLR 31 from Australia has multiple resistance mechanisms, including both non-target site cross resistance and target site cross resistance. The majority of the SLR 31 population has enhanced metabolism of chlorsulfuron and diclofop-methyl and a mechanism correlated with altered plasma membrane response, which correlates with resistance to some APP and cyclohexanedione (CHD) herbicides. A small proportion of the population also has target site cross resistance to APP and CHD herbicides. While A myosuroides and L. rigidum share common biological elements, they are not unique. Non-target site cross resistance and multiple herbicide resistance is predicted to develop in other weed species. The repercussions of cross and multiple resistance warrant proactive measures to prevent or delay onset.

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Metabolism-Based Herbicide Resistance, the Major Threat Among the Non-Target Site Resistance Mechanisms

Outlooks on Pest Management ◽

10.1564/v31_aug_04 ◽

2020 ◽

Vol 31 (4) ◽

pp. 162-168

Author(s):

Carlos A. G. Rigon ◽

Todd A. Gaines ◽

Anita Küpper ◽

Franck E. Dayan

Keyword(s):

Herbicide Resistance ◽

Resistance Mechanisms ◽

Target Site ◽

Major Threat ◽

Evolution Of Resistance ◽

Target Site Resistance ◽

Metabolic Degradation ◽

Varied Chemical ◽

Resistance To Herbicides ◽

Global Food

Evolution of resistance to pesticides is a problem challenging the sustainability of global food production. Resistance to herbicides is driven by the intense selection pressure imparted by synthetic herbicides on which we rely to manage weeds. Target-site resistance (TSR) mechanisms involve changes to the herbicide target protein and provide resistance only to herbicides within a single mechanism of action. Non-target site resistance (NTSR) mechanisms reduce the quantity of herbicide reaching the target site and/or modify the herbicide. NTSR mechanisms include reduced absorption and/or translocation, increased sequestration, and enhanced metabolic degradation. Of these diverse mechanisms contributing to NTSR, metabolism-based herbicide resistance represents a major threat because it can impart resistance to herbicides from varied chemical classes across any number of mechanisms of action.

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Non-Target-Site Resistance Mechanisms Endow Multiple Herbicide Resistance to Five Mechanisms of Action in Conyza bonariensis

Journal of Agricultural and Food Chemistry ◽

10.1021/acs.jafc.1c04279 ◽

2021 ◽

Author(s):

Candelario Palma-Bautista ◽

José G. Vázquez-García ◽

José Alfredo Domínguez-Valenzuela ◽

Kassio Ferreira Mendes ◽

Ricardo Alcántara de la Cruz ◽

...

Keyword(s):

Herbicide Resistance ◽

Resistance Mechanisms ◽

Mechanisms Of Action ◽

Target Site ◽

Conyza Bonariensis ◽

Target Site Resistance ◽

Multiple Herbicide Resistance

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Investigating the resistance levels and mechanisms to penoxsulam and cyhalofop-butyl in barnyardgrass (Echinochloa crus-galli) from Ningxia province, China

Weed Science ◽

10.1017/wsc.2021.37 ◽

2021 ◽

pp. 1-25

Author(s):

Qian Yang ◽

Xia Yang ◽

Zichang Zhang ◽

Jieping Wang ◽

Weiguo Fu ◽

...

Keyword(s):

Herbicide Resistance ◽

Molecular Mechanisms ◽

Acetolactate Synthase ◽

Rice Fields ◽

Target Site ◽

Herbicide Resistant ◽

Susceptible Populations ◽

High Level ◽

Als Inhibitor ◽

Encoding Genes

Abstract Barnyardgrass (Echinochloa crus-galli) is a noxious grass weed which infests rice fields and causes huge crop yield losses. In this study, we collected twelve E. crus-galli populations from rice ﬁelds of Ningxia province in China and investigated the resistance levels to acetolactate synthase (ALS) inhibitor penoxsulam and acetyl-CoA carboxylase (ACCase) inhibitor cyhalofop-butyl. The results showed that eight populations exhibited resistance to penoxsulam and four populations evolved resistance to cyhalofop-butyl. Moreover, all of the four cyhalofop-butyl-resistant populations (NX3, NX4, NX6 and NX7) displayed multiple-herbicide-resistance (MHR) to both penoxsulam and cyhalofop-butyl. The alternative herbicides bispyribac-sodium, metamifop and fenoxaprop-P-ethyl cannot effectively control the MHR plants. To characterize the molecular mechanisms of resistance, we ampliﬁed and sequenced the target-site encoding genes in resistant and susceptible populations. Partial sequences of three ALS genes and six ACCase genes were examined. A Trp-574-Leu mutation was detected in EcALS1 and EcALS3 in two high-level (65.84- and 59.30-fold) penoxsulam-resistant populations NX2 and NX10, respectively. In addition, one copy (EcACC4) of ACCase genes encodes a truncated aberrant protein due to a frameshift mutation in E. crus-galli populations. None of amino acid substitutions that are known to confer herbicide resistance were detected in ALS and ACCase genes of MHR populations. Our study reveals the widespread of multiple-herbicide resistant E. crus-galli populations at Ningxia province of China that exhibit resistance to several ALS and ACCase inhibitors. Non-target-site based mechanisms are likely to be involved in E. crus-galli resistance to the herbicides, at least in four MHR populations.

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Pollen-mediated gene flow and transfer of resistance alleles from herbicide-resistant broadleaf weeds

Weed Technology ◽

10.1017/wet.2020.101 ◽

2020 ◽

pp. 1-15

Author(s):

Amit J. Jhala ◽

Jason K. Norsworthy ◽

Zahoor A. Ganie ◽

Lynn M. Sosnoskie ◽

Hugh J. Beckie ◽

...

Keyword(s):

Gene Flow ◽

Reproductive Biology ◽

Interspecific Hybridization ◽

Herbicide Resistance ◽

Palmer Amaranth ◽

High Genetic Diversity ◽

Widespread Occurrence ◽

Common Lambsquarters ◽

Herbicide Resistant ◽

Giant Ragweed

Abstract Pollen-mediated gene flow (PMGF) refers to the transfer of genetic information (alleles) from one plant to another compatible plant. With the evolution of herbicide-resistant (HR) weeds, PMGF plays an important role in the transfer of resistance alleles from HR to susceptible weeds; however, little attention is given to this topic. The objective of this work was to review reproductive biology, PMGF studies, and interspecific hybridization, as well as potential for herbicide resistance alleles to transfer in the economically important broadleaf weeds including common lambsquarters, giant ragweed, horseweed, kochia, Palmer amaranth, and waterhemp. The PMGF studies involving these species reveal that transfer of herbicide resistance alleles routinely occurs under field conditions and is influenced by several factors, such as reproductive biology, environment, and production practices. Interspecific hybridization studies within Amaranthus and Ambrosia spp. show that herbicide resistance allele transfer is possible between species of the same genus but at relatively low levels. The widespread occurrence of HR weed populations and high genetic diversity is at least partly due to PMGF, particularly in dioecious species such as Palmer amaranth and waterhemp compared with monoecious species such as common lambsquarters and horseweed. Prolific pollen production in giant ragweed contributes to PMGF. Kochia, a wind-pollinated species can efficiently disseminate herbicide resistance alleles via both PMGF and tumbleweed seed dispersal, resulting in widespread occurrence of multiple HR kochia populations. The findings from this review verify that intra- and interspecific gene flow can occur and, even at a low rate, could contribute to the rapid spread of herbicide resistance alleles. More research is needed to determine the role of PMGF in transferring multiple herbicide resistance alleles at the landscape level.

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

Weed Science ◽

10.1614/ws-d-09-00037.1 ◽

2010 ◽

Vol 58 (2) ◽

pp. 109-117 ◽

Cited By ~ 48

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.

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

Weed Science ◽

10.1017/wsc.2017.69 ◽

2017 ◽

Vol 66 (2) ◽

pp. 234-245 ◽

Cited By ~ 8

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.

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