scholarly journals The First Report of Target-Site Resistance to Glyphosate in Sweet Summer Grass (Moorochloa eruciformis)

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1885
Author(s):  
Romesh Salgotra ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Amino Acid ◽  
Management Strategies ◽  
Glyphosate Resistance ◽  
Target Site ◽  
Single Amino Acid ◽  
Invasive Weeds ◽  
Epsps Gene ◽  
Target Site Resistance ◽  
Multiple Amino Acid ◽  
First Time

Sweet summer grass is a problematic weed in the central Queensland region of Australia. This study found glyphosate resistance in two biotypes (R1 and R2) of sweet summer grass. The level of resistance in these biotypes was greater than 8-fold. The glyphosate dose required to reduce dry matter by 50% (GR50) for the resistant populations varied from 1993 to 2100 g ha−1. A novel glyphosate resistance double point mutation in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene was identified for the first time in sweet summer grass. Multiple mutations, including multiple amino acid changes at the glyphosate target site, as well as mutations involving two nucleotide changes at a single amino acid codon, were observed. Both resistant biotypes exhibited a nucleotide change of CAA to ACA in codon 106, which predicts an amino acid change of proline to a threonine (Pro-106-Thr). In addition, the R1 biotype also possessed a mutation at codon 100, where a nucleotide substitution of T for G occurred (GCT to TCT), resulting in a substitution of serine for alanine (Ala-100-Ser). Understanding the molecular mechanism of glyphosate resistance will help to design effective management strategies to control invasive weeds.

scholarly journals Target-Site Resistance to Glyphosate in Chloris Virgata Biotypes and Alternative Herbicide Options for its Control

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1266
Author(s):  
Het Samir Desai ◽  
Michael Thompson ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Glyphosate Resistance ◽  
Target Site ◽  
Site Mutation ◽  
Glufosinate Ammonium ◽  
Epsps Gene ◽  
First Case ◽  
Target Site Resistance ◽  
Chloris Virgata ◽  
Moderately Resistant ◽  
Dose Response Study

Due to the overdependence on glyphosate to manage weeds in fallow conditions, glyphosate resistance has developed in various biotypes of several grass weeds, including Chloris virgata Sw. The first case of glyphosate resistance in C. virgata was found in 2015 in Australia, and since then several cases have been confirmed in several biotypes across Australia. Pot studies were conducted with 10 biotypes of C. virgata to determine glyphosate resistance levels. The biotypes were identified as either susceptible, moderately resistant or highly resistant based on the glyphosate dose required to kill 50% of plants. Two glyphosate-susceptible (GS) and two glyphosate-resistant (GR) biotypes were identified by the dose-response study and analyzed for the presence of target-site mutation in the 5–enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene. Performance of alternative herbicides to glyphosate as well as the double-knock herbicide approach was evaluated on the two GS (Ch and SGM2) and two GR (SGW2 and CP2) biotypes. Three herbicides, clethodim, haloxyfop and paraquat, were found to be effective (100% control) against all four biotypes when applied at the 4–5 leaf stage. All the sequential herbicide treatments, such as glyphosate followed by paraquat and glufosinate-ammonium followed by paraquat, provided 100% control of all four biotypes of C. virgata. This study identified effective herbicide options for the control of GR C. virgata and showed that target-site mutations were involved in the resistance of two biotypes to glyphosate (SGW2 and CP2). Results could aid farmers in selecting herbicides to manage C. virgata in their fields.

scholarly journals Target-Site Mutations Conferring Herbicide Resistance

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 382 ◽  
Author(s):  
Brent P. Murphy ◽  
Patrick J. Tranel
Keyword(s):  
Amino Acid ◽  
Herbicide Resistance ◽  
Target Site ◽  
Single Amino Acid ◽  
Cross Resistance ◽  
Target Sites ◽  
Resistance Patterns ◽  
Experimental Approaches ◽  
Sites Of Action ◽  
Multiple Amino Acid

Mutations conferring evolved herbicide resistance in weeds are known in nine different herbicide sites of action. This review summarizes recently reported resistance-conferring mutations for each of these nine target sites. One emerging trend is an increase in reports of multiple mutations, including multiple amino acid changes at the glyphosate target site, as well as mutations involving two nucleotide changes at a single amino acid codon. Standard reference sequences are suggested for target sites for which standards do not already exist. We also discuss experimental approaches for investigating cross-resistance patterns and for investigating fitness costs of specific target-site mutations.

Single Amino Acid Based Self-Assemblies of Cysteine and Methionine

2018 ◽  
Author(s):  
Nidhi Gour ◽  
Bharti Koshti ◽  
Chandra Kanth P. ◽  
Dhruvi Shah ◽  
Vivek Shinh Kshatriya ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Self Assembly ◽  
Aromatic Amino Acids ◽  
Neutral Condition ◽  
Single Amino Acid ◽  
Binding Assays ◽  
Human Neuroblastoma ◽  
Cytotoxicity Assays ◽  
First Time

We report for the very first time self-assembly of Cysteine and Methionine to discrenible strucutres under neutral condition. To get insights into the structure formation, thioflavin T and Congo red binding assays were done which revealed that aggregates may not have amyloid like characteristics. The nature of interactions which lead to such self-assemblies was purported by coincubating assemblies in urea and mercaptoethanol. Further interaction of aggregates with short amyloidogenic dipeptide diphenylalanine (FF) was assessed. While cysteine aggregates completely disrupted FF fibres, methionine albeit triggered fibrillation. The cytotoxicity assays of cysteine and methionine structures were performed on Human Neuroblastoma IMR-32 cells which suggested that aggregates are not cytotoxic in nature and thus, may not have amyloid like etiology. The results presented in the manuscript are striking, since to the best of our knowledge,this is the first report which demonstrates that even non-aromatic amino acids (cysteine and methionine) can undergo spontaneous self-assembly to form ordered aggregates.

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

Weed Science ◽  
2010 ◽  
Vol 58 (2) ◽  
pp. 109-117 ◽  
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.

Glyphosate resistance inAmbrosia trifida:Part 2. Rapid response physiology and non-target-site resistance

2017 ◽  
Vol 74 (5) ◽  
pp. 1079-1088 ◽  
Author(s):  
Marcelo L Moretti ◽  
Christopher R Van Horn ◽  
Renae Robertson ◽  
Kabelo Segobye ◽  
Stephen C Weller ◽  
...  
Keyword(s):  
Glyphosate Resistance ◽  
Rapid Response ◽  
Target Site ◽  
Target Site Resistance

scholarly journals The Triple Amino Acid Substitution TAP-IVS in the EPSPS Gene Confers High Glyphosate Resistance to the Superweed Amaranthus hybridus

2019 ◽  
Vol 20 (10) ◽  
pp. 2396 ◽  
Author(s):  
Maria J. García ◽  
Candelario Palma-Bautista ◽  
Antonia M. Rojano-Delgado ◽  
Enzo Bracamonte ◽  
João Portugal ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Glyphosate Resistance ◽  
Wild Type ◽  
Triple Mutant ◽  
Resistance Level ◽  
Amaranthus Hybridus ◽  
Susceptible Population ◽  
Epsps Gene ◽  
Wide Range

The introduction of glyphosate-resistant (GR) crops revolutionized weed management; however, the improper use of this technology has selected for a wide range of weeds resistant to glyphosate, referred to as superweeds. We characterized the high glyphosate resistance level of an Amaranthus hybridus population (GRH)—a superweed collected in a GR-soybean field from Cordoba, Argentina—as well as the resistance mechanisms that govern it in comparison to a susceptible population (GSH). The GRH population was 100.6 times more resistant than the GSH population. Reduced absorption and metabolism of glyphosate, as well as gene duplication of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) or its overexpression did not contribute to this resistance. However, GSH plants translocated at least 10% more 14C-glyphosate to the rest of the plant and roots than GRH plants at 9 h after treatment. In addition, a novel triple amino acid substitution from TAP (wild type, GSH) to IVS (triple mutant, GRH) was identified in the EPSPS gene of the GRH. The nucleotide substitutions consisted of ATA102, GTC103 and TCA106 instead of ACA102, GCG103, and CCA106, respectively. The hydrogen bond distances between Gly-101 and Arg-105 positions increased from 2.89 Å (wild type) to 2.93 Å (triple-mutant) according to the EPSPS structural modeling. These results support that the high level of glyphosate resistance of the GRH A. hybridus population was mainly governed by the triple mutation TAP-IVS found of the EPSPS target site, but the impaired translocation of herbicide also contributed in this resistance.

scholarly journals Evolution of Target-Site Resistance to Glyphosate in an Amaranthus palmeri Population from Argentina and Its Expression at Different Plant Growth Temperatures

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 512 ◽  
Author(s):  
Kaundun ◽  
Jackson ◽  
Hutchings ◽  
Galloway ◽  
Marchegiani ◽  
...  
Keyword(s):  
Fold Increase ◽  
Glyphosate Resistance ◽  
Target Site ◽  
Amaranthus Palmeri ◽  
Site Mutation ◽  
Medium Temperature ◽  
Soybean Field ◽  
Over Expression ◽  
Target Site Resistance ◽  
The Difference

The mechanism and expression of resistance to glyphosate at different plant growing temperatures was investigated in an Amaranthus palmeri population (VM1) from a soybean field in Vicuña Mackenna, Cordoba, Argentina. Resistance was not due to reduced glyphosate translocation to the meristem or to EPSPS duplication, as reported for most US samples. In contrast, a proline 106 to serine target-site mutation acting additively with EPSPS over-expression (1.8-fold increase) was respectively a major and minor contributor to glyphosate resistance in VM1. Resistance indices based on LD50 values generated using progenies from a cross between 52 PS106 VM1 individuals were estimated at 7.1 for homozygous SS106 and 4.3 for heterozygous PS106 compared with homozygous wild PP106 plants grown at a medium temperature of 24 °C day/18 °C night. A larger proportion of wild and mutant progenies survived a single commonly employed glyphosate rate when maintained at 30 °C day/26 °C night compared with 20 °C day/16 night in a subsequent experiment. Interestingly, the P106S mutation was not identified in any of the 920 plants analysed from 115 US populations, thereby potentially reflecting the difference in A. palmeri control practices in Argentina and USA.

Evolved Glyphosate Resistance in Plants: Biochemical and Genetic Basis of Resistance

2006 ◽  
Vol 20 (2) ◽  
pp. 282-289 ◽  
Author(s):  
Stephen B. Powles ◽  
Christopher Preston
Keyword(s):  
Amino Acid ◽  
Resistance Mechanism ◽  
Nuclear Gene ◽  
Glyphosate Resistance ◽  
The United States ◽  
Resistance Mechanisms ◽  
Italian Ryegrass ◽  
Weed Species ◽  
Epsps Gene ◽  
Rigid Ryegrass

Resistance to the herbicide glyphosate is currently known in at least eight weed species from many countries. Some populations of goosegrass from Malaysia, rigid ryegrass from Australia, and Italian ryegrass from Chile exhibit target site–based resistance to glyphosate through changes at amino acid 106 of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene. Mutations change amino acid 106 from proline to either serine or threonine, conferring an EPSPS weakly resistant to glyphosate. The moderate level of resistance is sufficient for commercial failure of the herbicide to control these plants in the field. Conversely, a nontarget site resistance mechanism has been documented in glyphosate-resistant populations of horseweed and rigid ryegrass from the United States and Australia, respectively. In these resistant plants, there is reduced translocation of glyphosate to meristematic tissues. Both of these mechanisms are inherited as a single, nuclear gene trait. Although at present only two glyphosate-resistance mechanisms are known, it is likely that other mechanisms will become evident. The already very large and still increasing reliance on glyphosate in many parts of the world will inevitably result in more glyphosate-resistant weeds, placing the sustainability of this precious herbicide resource at risk.

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.

scholarly journals Molecular epidemiology of Aleutian mink disease virus from fecal swab of mink in northeast China

2020 ◽  
Author(s):  
Mingwei Tong ◽  
Na Sun ◽  
Zhigang Cao ◽  
Yuening Cheng ◽  
Miao Zhang ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Amino Acid ◽  
Molecular Epidemiology ◽  
Northeast China ◽  
Hypervariable Region ◽  
Single Amino Acid ◽  
High Genetic Diversity ◽  
Vp2 Gene ◽  
Single Amino Acid Residue ◽  
First Time

Abstract Background: Aleutian mink disease parvovirus (AMDV) causes Aleutian mink disease (AMD), which is a serious infectious disease of mink. The aim of this study was to get a better understanding of the molecular epidemiology of AMDV in northeast China to control and prevent AMD from further spreading. This study for the first time isolated AMDV from fecal swab samples of mink in China. Results: A total of 157/291 (54.0%) of the fecal swab samples were positive for AMDV. Of these, 23 AMDV positive samples were randomly selected for sequence alignment and phylogenetic analysis based on the acquired partial fragments of VP2 gene with the hypervariable region. Comparative DNA sequence analysis of 23 AMDV isolates with a reference nonpathogenic (AMDV-G) strain revealed 8.3% difference in partial VP2 nucleotide sequences. Amino acid alignment indicated the presence of several genetic variants, as well as one single amino acid residue deletion . The most concentrated area of variation was located in the hypervariable region of VP2 protein. According to phylogenetic analysis, the Chinese AMDV strains and the other 14 reference AMDV strains from different countries clustered into three groups (clades A, B and C). Most of the newly sequenced strains were found to form a Chinese-specific group, which solely consisted of Chinese AMDV strains. Conclusion: These findings indicated that a high genetic diversity was found in Chinese AMDV strains and the virus distribution were not dependent on geographical origin. Both local and imported AMDV positive species were prevalent in the Chinese mink farming population. The genetic evidence of AMDV variety and epidemic isolates have importance in mink farming practice.

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