Evolution of multiple target‐site resistance mechanisms in individual plants of glyphosate‐resistant Eleusine indica from China

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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Multiple Herbicide-Resistant Weeds and Non-target Site Resistance Mechanisms: A Global Challenge for Food Production

10.3389/978-2-88971-908-2 ◽

2021 ◽

Keyword(s):

Food Production ◽

Resistance Mechanisms ◽

Target Site ◽

Herbicide Resistant ◽

Global Challenge ◽

Target Site Resistance

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First Report of Glyphosate-Resistant Biotype of Eleusine Indica (L.) Gaertn. in Europe

Agronomy ◽

10.3390/agronomy10111692 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1692

Author(s):

Donato Loddo ◽

Gaetano Imperatore ◽

Andrea Milani ◽

Silvia Panozzo ◽

Silvia Farinati ◽

...

Keyword(s):

Weight Reduction ◽

Southern Italy ◽

Resistance Index ◽

Resistance Mechanisms ◽

Fresh Weight ◽

Eleusine Indica ◽

Dna Analyses ◽

Plant Nursery ◽

Resistant Population ◽

Target Site Resistance

Glyphosate-resistant biotypes of Eleusine indica (L.) Gaertn. have been detected in Asia, the Americas but not in Europe. The aim of this study was to evaluate resistance levels and possible target site resistance mechanisms of an E. indica biotype (19-1) collected from a plant nursery in Southern Italy where poor glyphosate efficacy was reported. Two dose-response experiments were conducted to evaluate the sensitivity of biotype 19-1 to glyphosate in comparison with two susceptible checks. 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) sequencing was performed to identify possible mutations conferring the resistance. The susceptible biotypes were completely controlled at the glyphosate recommended field dose of 360 g ae ha−1, while 50% of the plants of biotype 19-1 survived at 1440 g ae ha−1. The resistance index of biotype 19-1 ranged between 5.8 and 7.3 for the response variables of fresh weight reduction and plant survival, respectively. All the plants surviving glyphosate application and sampled for DNA analyses had the point mutation P106A. The biotype 19-1 can be confirmed as glyphosate-resistant, representing the first glyphosate-resistant population of E. indica in Europe.

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

Planta Daninha ◽

10.1590/s0100-83582012000300025 ◽

2012 ◽

Vol 30 (3) ◽

pp. 675-681 ◽

Cited By ~ 11

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.

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Insecticide resistance selection and reversal in two strains of Aedes aegypti

Wellcome Open Research ◽

10.12688/wellcomeopenres.15974.1 ◽

2020 ◽

Vol 5 ◽

pp. 183

Author(s):

Jonathan Thornton ◽

Bruno Gomes ◽

Constância Ayres ◽

Lisa Reimer

Keyword(s):

Aedes Aegypti ◽

Insecticide Resistance ◽

Vector Competence ◽

Resistance Mechanisms ◽

Target Site ◽

Metabolic Resistance ◽

Resistance Selection ◽

Similar Phenotype ◽

Target Site Resistance ◽

Homozygous Resistant

Background: Laboratory reared mosquito colonies are essential tools to understand insecticide action. However, they differ considerably from wild populations and from each other depending on their origin and rearing conditions, which makes studying the effects of specific resistance mechanisms difficult. This paper describes our methods for establishing multiple resistant strains of Aedes aegypti from two colonies as a new resource for further research on metabolic and target site resistance. Methods: Two resistant colonies of Ae. aegypti, from Cayman and Recife, were selected through 10 generations of exposure to insecticides including permethrin, malathion and temephos, to yield eight strains with different profiles of resistance due to either target site or metabolic resistance. Resistance ratios for each insecticide were calculated for the selected and unselected strains. The frequency of kdr alleles in the Cayman strains was determined using TaqMan assays. A comparative gene expression analysis among Recife strains was conducted using qPCR in larvae (CCae3A, CYP6N12, CYP6F3, CYP9M9) and adults (CCae3A, CYP6N12, CYP6BB2, CYP9J28a). Results: In the selected strain of Cayman, mortality against permethrin reduced almost to 0% and kdr became fixated by 5 generations. A similar phenotype was seen in the unselected homozygous resistant colony, whilst mortality in the susceptible homozygous colony rose to 82.9%. The Recife strains showed different responses between exposure to adulticide and larvicide, with detoxification genes in the temephos selected strain staying similar to the baseline, but a reduction in detoxification genes displayed in the other strains. Conclusions: These selected strains, with a range of insecticide resistance phenotypes and genotypes, will support further research on the effects of target-site and/or metabolic resistance mechanisms on various life-history traits, behaviours and vector competence of this important arbovirus vector.

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

Plants ◽

10.3390/plants10081703 ◽

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.

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Multiple target site resistance to glyphosate in junglerice (Echinochloa colona ) lines from California orchards

Pest Management Science ◽

10.1002/ps.5061 ◽

2018 ◽

Vol 74 (12) ◽

pp. 2747-2753 ◽

Cited By ~ 5

Author(s):

Sarah Morran ◽

Marcelo L Moretti ◽

Caio A Brunharo ◽

Albert J Fischer ◽

Bradley D Hanson

Keyword(s):

Target Site ◽

Multiple Target ◽

Target Site Resistance

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Genome-wide gene expression profiling reveals that cuticle alterations and P450 detoxification are associated with pyrethroid resistance in Anopheles arabiensis populations from Ethiopia

10.1101/451336 ◽

2018 ◽

Author(s):

Eba Alemayehu Simma ◽

Wannes Dermauw ◽

Vasileia Balabanidou ◽

Simon Snoeck ◽

Astrid Bryon ◽

...

Keyword(s):

Insecticide Resistance ◽

Anopheles Arabiensis ◽

Pyrethroid Resistance ◽

Resistance Mutation ◽

Resistance Mechanisms ◽

Target Site ◽

Malaria Vectors ◽

Metabolic Resistance ◽

Genome Wide ◽

Target Site Resistance

AbstractBACKGROUNDVector control is the main intervention in malaria control and elimination strategies. However, the development of insecticide resistance is one of the major challenges for controlling malaria vectors. Anopheles arabiensis populations in Ethiopia showed resistance against both DDT and the pyrethroid deltamethrin. Although a L1014F target-site resistance mutation was present in the voltage gated sodium channel of investigated populations, the levels of resistance and biochemical studies indicated the presence of additional resistance mechanisms. In this study, we used genome-wide transcriptome profiling by RNAseq to assess differentially expressed genes between three deltamethrin and DDT resistant An. arabiensis field populations (Tolay, Asendabo, Chewaka) and two susceptible strains (Sekoru and Mozambique).RESULTSBoth RNAseq analysis and RT-qPCR showed that a glutathione-S-transferase, gstd3, and a cytochrome P450 monooxygenase, cyp6p4, were significantly overexpressed in the group of resistant populations compared to the susceptible strains, suggesting that the enzymes they encode play a key role in metabolic resistance against deltamethrin or DDT. Furthermore, a gene ontology enrichment analysis showed that expression changes of cuticle related genes were strongly associated with insecticide resistance, although this did not translate in increased thickness of the procuticle.CONCLUSIONOur transcriptome sequencing of deltamethrin/DDT resistant An. arabiensis populations from Ethiopia suggests non-target site resistance mechanisms and pave the way for further investigation of the role of cuticle composition in resistance.

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