scholarly journals Identification of glyphosate resistance in Lolium rigidum Gaudin

2011 ◽  
Vol 26 (4) ◽  
pp. 393-399 ◽  
Author(s):  
Danijela Pavlovic ◽  
Charlie Reinhardt ◽  
Igor Elezovic ◽  
Sava Vrbnicanin
Keyword(s):  
Shikimic Acid ◽  
Glyphosate Resistance ◽  
The Other ◽  
Population Difference ◽  
Lolium Rigidum ◽  
Susceptible Population ◽  
Dry Biomass ◽  
Rigid Ryegrass ◽  
Susceptible Populations ◽  
Two Populations

Glyphosate resistance was found in Lolium rigidum Gaudin (Rigid ryegrass, LOLRI) in South Africa. Suspected glyphosate-resistant L. rigidum populations were collected and grown under greenhouse conditions. The plants were sprayed with a range of doses of glyphosate 35 days after planting and shoot dry biomass was determined 17 days after herbicide treatment. Based on the dose-response experiment conducted in the greenhouse, one population of L. rigidum suspected to be resistant to glyphosate was approximately 5.3 fold more resistant than susceptible population. The other population was 2.8 fold more resistant than susceptible population. Difference between the two suspected resistant populations was 1.9 fold. All plants were treated with glyphosate (1000 g a.i. ha-1) and shikimic acid was extracted 2, 4 and 6 days after treatment. The plants of susceptible populations accumulated more shikimic acid than other two populations.

Rigid Ryegrass (Lolium rigidum) Populations Containing a Target Site Mutation in EPSPS and Reduced Glyphosate Translocation Are More Resistant to Glyphosate

Weed Science ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 474-479 ◽  
Author(s):  
Yazid Bostamam ◽  
Jenna M. Malone ◽  
Fleur C. Dolman ◽  
Peter Boutsalis ◽  
Christopher Preston
Keyword(s):  
Weed Control ◽  
Glyphosate Resistance ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Lolium Rigidum ◽  
Site Mutation ◽  
Susceptible Population ◽  
Intensive Use ◽  
Rigid Ryegrass ◽  
Two Populations

Glyphosate is widely used for weed control in the grape growing industry in southern Australia. The intensive use of glyphosate in this industry has resulted in the evolution of glyphosate resistance in rigid ryegrass. Two populations of rigid ryegrass from vineyards, SLR80 and SLR88, had 6- to 11-fold resistance to glyphosate in dose-response studies. These resistance levels were higher than two previously well-characterized glyphosate-resistant populations of rigid ryegrass (SLR77 and NLR70), containing a modified target site or reduced translocation, respectively. Populations SLR80 and SLR88 accumulated less glyphosate, 12 and 17% of absorbed glyphosate, in the shoot in the resistant populations compared with 26% in the susceptible population. In addition, a mutation within the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) where Pro106had been substituted by either serine or threonine was identified. These two populations are more highly resistant to glyphosate as a consequence of expressing two different resistance mechanisms concurrently.

Evolved resistance to glyphosate in rigid ryegrass (Lolium rigidum) in Australia

Weed Science ◽  
1998 ◽  
Vol 46 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Stephen B. Powles ◽  
Debrah F. Lorraine-Colwill ◽  
James J. Dellow ◽  
Christopher Preston
Keyword(s):  
Dose Response ◽  
Glyphosate Resistance ◽  
Cross Resistance ◽  
Lolium Rigidum ◽  
Weed Species ◽  
Susceptible Population ◽  
Use Patterns ◽  
Rigid Ryegrass ◽  
Susceptible Populations ◽  
Grass Weed

Following 15 yr of successful use, glyphosate failed to control a population of the widespread grass weed rigid ryegrass in Australia. This population proved to be resistant to glyphosate in pot dose-response experiments conducted outdoors, exhibiting 7- to 11-fold resistance when compared to a susceptible population. Some cross-resistance to diclofop-methyl (about 2.5-fold) was also observed. Similar levels of control of the resistant and susceptible populations were obtained following application of amitrole, chlorsulfuron, fluazifop-P-butyl, paraquat, sethoxydim, sirnazine, or tralkoxydim. The presence of glyphosate resistance in a major weed species indicates a need for changes in glyphosate use patterns.

Reduced Glyphosate Translocation in Two Glyphosate-Resistant Populations of Rigid Ryegrass (Lolium rigidum) from Fence Lines in South Australia

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 4-10 ◽  
Author(s):  
Patricia Adu-Yeboah ◽  
Jenna M. Malone ◽  
Gurjeet Gill ◽  
Christopher Preston
Keyword(s):  
Dose Response ◽  
South Australia ◽  
Lolium Rigidum ◽  
Gene Encoding ◽  
Susceptible Population ◽  
Mechanism Of Resistance ◽  
Treated Leaf ◽  
Rigid Ryegrass ◽  
Susceptible Populations ◽  
Fence Line

Populations of rigid ryegrass with resistance to glyphosate have started to become a problem on fence lines of cropping fields of southern Australian farms. Seed of rigid ryegrass plants that survived glyphosate application were collected from two fence line locations in Clare, South Australia. Dose–response experiments confirmed resistance of these fence line populations to glyphosate. Both populations required 9- to 15-fold higher glyphosate dose to achieve 50% mortality in comparison to a standard susceptible population. The mechanism of resistance in these populations was investigated. Sequencing a conserved region of the gene encoding 5-enolpyruvyl-shikimate-3-phosphate synthase identified no differences between the resistant and susceptible populations. Absorption of glyphosate into leaves of the resistant populations was not different from the susceptible population. However, the resistant plants retained significantly more herbicide in the treated leaf blades than did the susceptible plants. Conversely, susceptible plants translocated significantly more herbicide to the leaf sheaths and untreated leaves than the resistant plants. The differences in translocation pattern for glyphosate between the resistant and susceptible populations of rigid ryegrass suggest resistance is associated with altered translocation of glyphosate in the fence line populations.

scholarly journals Inheritance of glyphosate resistance in rigid ryegrass (Lolium rigidum) from California

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 615-619 ◽  
Author(s):  
Marulak Simarmata ◽  
Suleiman Bughrara ◽  
Donald Penner
Keyword(s):  
First Generation ◽  
Recurrent Selection ◽  
Maternal Inheritance ◽  
Glyphosate Resistance ◽  
Segregation Ratio ◽  
Lolium Rigidum ◽  
Response Curves ◽  
Mendelian Segregation ◽  
Rigid Ryegrass ◽  
Homozygous Resistant

Glyphosate resistance was found in a rigid ryegrass population in northern California. A sample of the resistant plants were collected and grown under greenhouse conditions. The objective of this study was to evaluate glyphosate resistance in the progeny of the collected plants by recurrent selection, obtain the homozygous resistant and sensitive lines to establish dose-response curves, and to determine the inheritance of glyphosate resistance in rigid ryegrass. Diverse levels of resistance were observed in the first generation with survival of 89, 59, 45, and 9% from glyphosate at 1x, 2x, 4x, and 8x respectively, where x = 1.12 kg ha−1isopropylamine salt of glyphosate. Clones of plants that died from 1x were allowed to produce seed and were further subjected to recurrent selection to generate the most sensitive plants (S lines), which died from 0.125x glyphosate. The most resistant plants (R lines) were generated from the survivors receiving 8x glyphosate. The ratio between I50rates for the glyphosate resistant and the glyphosate sensitive plants was > 100-fold. The R and S lines were crossed reciprocally and F1progeny of both (R × S) and (S × R) showed intermediate resistance. These survived up to 2x glyphosate. The F2progeny were generated by intercrossing of F1plants. The ratio of sensitive, intermediate, and resistant plants in the F2population before the treatment of glyphosate at 0.125x followed by 8x was 1 : 16, 14 : 16, and 1 : 16 respectively, which corresponded to the Mendelian segregation ratio of two genes. The results indicated that the inheritance of glyphosate resistance in rigid ryegrass from California appeared to be nuclear, incompletely dominant, multigenic, and pollen-transmitted with no indication of maternal inheritance.

Frost Reduces Clethodim Efficacy in Clethodim-Resistant Rigid Ryegrass (Lolium rigidum) Populations

Weed Science ◽  
2016 ◽  
Vol 64 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Rupinder Kaur Saini ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet S. Gill
Keyword(s):  
Dose Response ◽  
Coenzyme A ◽  
Resistance Mechanism ◽  
Lolium Rigidum ◽  
Weed Species ◽  
Susceptible Population ◽  
Acetyl Coenzyme A ◽  
Survival Percentage ◽  
Rigid Ryegrass ◽  
Acetyl Coenzyme A Carboxylase

Rigid ryegrass, an important annual weed species in cropping regions of southern Australia, has evolved resistance to 11 major groups of herbicides. Dose–response studies were conducted to determine response of three clethodim-resistant populations and one clethodim-susceptible population of rigid ryegrass to three different frost treatments (−2 C). Clethodim-resistant and -susceptible plants were exposed to frost in a frost chamber from 4:00 P.M. to 8:00 A.M. for three nights before or after clethodim application and were compared with plants not exposed to frost. A reduction in the level of clethodim efficacy was observed in resistant populations when plants were exposed to frost for three nights before or after clethodim application. In the highly resistant populations, the survival percentage and LD50were higher when plants were exposed to frost before clethodim application compared with frost after clethodim application. However, frost treatment did not influence clethodim efficacy of the susceptible population. Sequencing of the acetyl coenzyme A carboxylase (ACCase) gene of the three resistant populations identified three known mutations at positions 1781, 2041, and 2078. However, most individuals in the highly resistant populations did not contain any known mutation in ACCase, suggesting the resistance mechanism was a nontarget site. The effect of frost on clethodim efficacy in resistant plants may be an outcome of the interaction between frost and the clethodim resistance mechanism(s) present.

scholarly journals New Case of False-Star-Grass (Chloris distichophylla) Population Evolving Glyphosate Resistance

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 377 ◽  
Author(s):  
José G. Vázquez-García ◽  
Sajedeh Golmohammadzadeh ◽  
Candelario Palma-Bautista ◽  
Antonia M. Rojano-Delgado ◽  
José A. Domínguez-Valenzuela ◽  
...  
Keyword(s):  
Weed Management ◽  
Chemical Control ◽  
Shikimic Acid ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Integrated Weed Management ◽  
Resistance Level ◽  
Susceptible Population ◽  
First Case

Chloris distichophylla, suspected of glyphosate resistance (GR), was collected from areas of soybean cultivation in Rio Grande do Sul, Brazil. A comparison was made with a susceptible population (GS) to evaluate the resistance level, mechanisms involved, and control alternatives. Glyphosate doses required to reduce the dry weight (GR50) or cause a mortality rate of 50% (LD50) were around 5.1–3 times greater in the GR population than in the GS population. The shikimic acid accumulation was around 6.2-fold greater in GS plants than in GR plants. No metabolized glyphosate was found in either GR or GS plants. Both populations did not differ in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) basal activity or in vitro inhibition of EPSPS activity by glyphosate (I50). The maximum glyphosate absorption was observed at 96 hours after treatment (HAT), which was twofold higher in the GS plants than in the GR plants. This confirms the first case of glyphosate resistance in C. distichophylla. In addition, at 96 HAT, the GS plants translocated more 14C-glyphosate than the GR ones. The best options for the chemical control of both C. distichophylla populations were clethodim, quizalofop, paraquat, glufosinate, tembotrione, diuron, and atrazine. The first case of glyphosate resistance in C. distichophylla was due to impaired uptake and translocation. Chemical control using multiple herbicides with different modes of action (MOA) could be a tool used for integrated weed management (IWM) programs.

First Case of Multiple Resistance to Glyphosate and PPO-inhibiting Herbicides in Rigid Ryegrass (Lolium rigidum) in Spain

Weed Science ◽  
2017 ◽  
Vol 65 (6) ◽  
pp. 690-698 ◽  
Author(s):  
Pablo Tomas Fernandez-Moreno ◽  
Antonia Maria Rojano-Delgado ◽  
Julio Menendez ◽  
Rafael De Prado
Keyword(s):  
Dose Response ◽  
Selection Pressure ◽  
Protoporphyrin Ix ◽  
Glyphosate Resistance ◽  
Resistance Pattern ◽  
Multiple Resistance ◽  
Lolium Rigidum ◽  
First Case ◽  
Natural Tendency ◽  
Rigid Ryegrass

Five rigid ryegrass populations suspected of being resistant to both glyphosate and oxyfluorfen were collected in southern Spain and tested under laboratory-controlled conditions. Four populations (Depuradora, Condado, AlamoRasilla, and Portichuelo) were treated with glyphosate for at least 15 consecutive years, and treatments during the last 5 yr were mixed with oxyfluorfen. The fifth population (4alamos) followed the same glyphosate treatment, although oxyfluorfen was never used to control it. Dose–response assays confirmed glyphosate resistance in all populations, with resistance indexes ranging from 11.7 to 37.5 (GR90). Shikimate accumulation assays consistently supported these data, as the most glyphosate-resistant populations (Depuradora and Condado) displayed the lowest shikimate levels. Surprisingly, four populations (Depuradora, Condado, AlamoRasilla, and Portichuelo) displayed 7.93- to 70.18-fold more resistance (GR90) to oxyfluorfen, despite limited selection pressure, showing a similar resistance pattern as that for glyphosate. The 4alamos population displayed oxyfluorfen GR90values that were similar to those observed in susceptible plants; however, this population was significantly more resistant in terms of plant survival (LD90). Protoporphyrin IX accumulation assays supported the results of dose–response assays, in that the most oxyfluorfen-resistant populations accumulated less protoporphyrin IX. Although more studies are needed, it seems that these five glyphosate-resistant weed populations display a natural tendency to easily develop resistance to oxyfluorfen, with the populations that have higher resistance to glyphosate also having higher resistance to oxyfluorfen.

Target Enzyme-Based Resistance to Clethodim inLolium rigidumPopulations in Australia

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 946-953 ◽  
Author(s):  
Rupinder Kaur Saini ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet Gill
Keyword(s):  
Effective Control ◽  
Cross Resistance ◽  
Single Plant ◽  
Susceptible Population ◽  
Ambient Temperatures ◽  
Resistant Population ◽  
Rigid Ryegrass ◽  
Moderately Resistant ◽  
Two Populations ◽  
Biomass Reduction

Clethodim resistance was identified in 12 rigid ryegrass populations from winter cropping regions in four different states of Australia. Clethodim had failed to provide effective control of these populations in the field and resistance was suspected. Dose–response experiments confirmed resistance to clethodim and butroxydim in all populations. During 2012, the LD50of resistant populations ranged from 10.2 to 89.3 g ha−1, making them 3 to 34–fold more resistant to clethodim than the susceptible population. Similarly, GR50of resistant population varied from 8 to 37.1 g ha−1, which is 3 to 13.9–fold higher than the susceptible population. In 2013, clethodim-resistant populations were 7.8 to 35.3–fold more resistant to clethodim than the susceptible population. The higher resistance factor in 2013, especially in moderately resistant populations, could have been associated with lower ambient temperatures during the winter of 2013. These resistant populations had also evolved cross-resistance to butroxydim. The resistant populations required 1.3 to 6.6–fold higher butroxydim dose to achieve 50% mortality and 3 to 27–fold more butroxydim for 50% biomass reduction compared to the standard susceptible population. Sequencing of the target-site ACCase gene identified five known ACCase substitutions (isoleucine-1781-leucine, isoleucine-2041-asparagine, aspartate-2078-glycine, and cysteine-2088-arginine, and glycine-2096-alanine) in these populations. In nine populations, multiple ACCase mutations were present in different individuals. Furthermore, two alleles with different mutations were present in a single plant of rigid ryegrass in two populations.

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