Mechanisms of glyphosate resistance and response to alternative herbicide‐based management in populations of the three <i>Conyza</i> species introduced in southern Spain

Amaro‐Blanco, Ignacio; Fernández-Moreno, Pablo T.; Osuna, M. D.; Bastida, Fernando

doi:10.1002/ps.4896

Cited by 31 publications

(62 citation statements)

References 47 publications

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“…In our case, there were no significant differences in terms of the EPSPS basal activity between the resistant and susceptible populations, with values ranging from 0.10 to 0.11 µmol phosphate µg total soluble protein (TSP) −1 (Figure 1). No additional data about Sorghum halepense EPSPS activity is available for comparison, but our values were similar to those observed in other glyphosate-susceptible EPSPS enzymes, such as those isolated from several Conyza species [26]. Therefore, even in a polyploidy species such as Johnsongrass, with multiple genes encoding the EPSPS protein, the overexpression of the EPSPS gene leading to multiple functional copies of the EPSPS protein does not seem to be the mechanism of resistance, as EPSPS basal activity remains the same no matter the biotype tested.…”

Section: Epsps Basal Activity and Inhibitionsupporting

confidence: 84%

“…Therefore, even in a polyploidy species such as Johnsongrass, with multiple genes encoding the EPSPS protein, the overexpression of the EPSPS gene leading to multiple functional copies of the EPSPS protein does not seem to be the mechanism of resistance, as EPSPS basal activity remains the same no matter the biotype tested. In addition, there were no significant differences in the 50% inhibition of EPSPS activity (I 50 ) values among all the populations tested, with estimated values ranging from 2.6 (GR6) to 3.4 (GR1) µM (Figure 1), which were even lower than those observed in other weed populations with glyphosate-susceptible EPSPS enzymes [26,27]. Therefore, a change of the sensitivity to glyphosate of the EPSPS enzyme is not the mechanism of resistance in the resistant populations.…”

Section: Epsps Basal Activity and Inhibitionmentioning

confidence: 78%

“…EPSPS enzyme activity was studied according to Amaro-Blanco et al [26]. Samples of 5 g of leaf tissue (three-to four-leaf growth stage) from each population were used for EPSPS extraction.…”

Section: Epsps Inhibition and Basal Activity Studymentioning

confidence: 99%

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The First Case of Glyphosate Resistance in Johnsongrass (Sorghum halepense (L.) Pers.) in Europe

Vázquez-García

Palma-Bautista

Rojano-Delgado

et al. 2020

Plants

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Six Johnsongrass populations suspected of being glyphosate resistant were collected from railways and freeways near Cordoba (SW Spain), where glyphosate is the main weed control tool. The 50% reduction in shoot fresh weight (GR 50 ) values obtained for these six populations ranged from 550.4 to 1169 g ae ha −1 , which were 4.2 to 9 times greater than the value obtained for the susceptible population. Glyphosate was equally metabolized to the same extent in both resistant and susceptible populations, with no significant differences in either 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibition or basal activity. No amino acid substitutions were observed in any of the resistant populations. Slight but significant differences in glyphosate penetration were observed among some but not all of the resistant populations and for the times of incubation assayed, although these differences were not considered further. The proposed primary mechanism of resistance in these six glyphosate-resistant Johnsongrass populations is reduced herbicide translocation, because the amount of glyphosate that translocated from treated leaves to shoots and roots in the susceptible population was double that observed in the resistant populations. As glyphosate multiple resistance due to more than one mechanism is not uncommon, this is the first time that glyphosate-resistant Johnsongrass populations have been fully described for all known mechanisms.

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Section: Epsps Basal Activity and Inhibitionsupporting

confidence: 84%

Section: Epsps Basal Activity and Inhibitionmentioning

confidence: 78%

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The First Case of Glyphosate Resistance in Johnsongrass (Sorghum halepense (L.) Pers.) in Europe

Vázquez-García

Palma-Bautista

Rojano-Delgado

et al. 2020

Plants

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“…Several studies have been conducted in Conyza spp. with the objectives to understand the GR mechanisms (Feng et al, 2004;Ferreira et al, 2008;Peng et al, 2010;Ge et al, 2014;Cardinali et al, 2015;Tani et al, 2015;Moretti et al, 2017;Kleinman and Rubin, 2017;González-Torralva et al, 2017;Hereward et al, 2018;Amaro-Blanco et al, 2018). These studies have found that the GR mechanisms are related to herbicide transport, translocation, uptake, metabolism, and alterations at the 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) enzyme, which is the glyphosate target site.…”

Section: Introductionmentioning

confidence: 99%

Does the Glyphosate Treatment Interfere Negatively on RNA Integrity in Glyphosate-Resistant and -Sensitive Conyza bonariensis?

et al. 2019

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The hairy fleabane (Conyza bonariensis (L.) Cronq.) is among the most problematic glyphosate-resistant weeds to manage around the world. In weed science, molecular approaches such as RNA sequencing (RNA-Seq) and quantitative reverse-transcription polymerase chain reaction (RT-qPCR) have been employed to study molecular responses to glyphosate treatment in Conyza species. Glyphosate treatment leads to reactive oxygen species (ROS) production in plants which could damage the RNA. Degraded RNA is an issue and can compromise further molecular analysis. Thus, the objective of this study was to evaluate whether glyphosate treatment interferes negatively on RNA integrity of glyphosate-resistant andsensitive hairy fleabane biotypes. Two experiments were performed using glyphosate doses from 0 to 11,840 g a.e. ha -1 and evaluated in a time-course until 288 hours after treatment. The total of 86 RNA samples were evaluated. The RNA integrity was evaluated in a Bioanalyzer 2100 equipment according to RNA integrity number (RIN) scores and electrophoresis gel. The RIN scores ranged from 5.1 to 9.0. Glyphosate doses do not reduce the RIN scores in both glyphosate-resistant and -sensitive biotypes of hairy fleabane. Visual and automatic analysis of electrophoresis gel show suitable results for all RNA samples, with well-defined bands at 28S and 18S positions and no degradation. The results of the analysis indicate that glyphosate treatment does not affect the RNA integrity of glyphosate-resistant and -sensitive biotypes of hairy fleabane until 288 and 192 hours after glyphosate treatment, respectively. The RNA integrity analysis provides useful results to evaluate the RNA condition for further analysis. However, the costs were around US$ 14.25 per sample, considering only reagents. These results are useful for planning future timecourse experiments in Conyza spp. after glyphosate treatment.Keywords: hairy fleabane, molecular analysis, RNA integrity number (RIN). (Conyza bonariensis (L.) Cronq.) está entre as plantas daninhas resistentes ao glifosato mais difíceis de serem manejadas em todo o mundo. Na ciência das plantas daninhas, abordagens moleculares, como o sequenciamento de RNA (RNA-Seq) e a reação da transcriptase reversa da polimerase em tempo real (RT-qPCR), têm sido empregadas para estudar as respostas moleculares ao tratamento com glifosato em espécies de Conyza. No entanto, o tratamento com glifosato leva à produção de espécies reativas de oxigênio (ROS) em plantas, que podem danificar o RNA. A degradação do RNA é um problema e pode comprometer futuras análises moleculares. Assim, o objetivo deste estudo foi avaliar se o tratamento com glifosato interfere negativamente na integridade do RNA de biótipos de buva resistente e sensível ao glifosato. Dois experimentos foram realizados I D I D I D Planta Daninha 2019; v37:e019217909 PIASECKI, C. et al. Does the glyphosate treatment interfere negatively on RNA integrity in glyphosate-resistant and -sensitive ... 2 utilizando doses de glifosato de 0 a 11.840 g e.a. ha -1 e av...

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“…Glyphosate inhibits the enzyme 5-enolpyruvlshikimate-3-phosphate synthase (EPSPS), which catalyzes the reaction of shikimate-3-phosphate and phosphoenolpyruvate to form 5-enolpyruvil-shikimate-3-phosphate (Fernandez et al, 2015;Gonz alez-Torralva et al, 2012). Inhibition of EPSPS prevents the biosynthesis of phenylalanine, tryptophan, tyrosine, and other aromatic compounds in sensitive plants (Amaro-Blanco et al, 2018;Tahmasebi et al, 2018). In Turkey, glyphosate is the most widely used herbicide and is registered on more than 70 crops, including peach (Torun, 2017).…”

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confidence: 99%

Sumatran Fleabane (Conyza sumatrensis) Resistance to Glyphosate in Peach Orchards in Turkey

İnci¹,

Galvin²,

Al‐Khatib³

et al. 2019

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Glyphosate has been widely used to control annual, perennial, and biennial weeds including Conyza species. Conyza sumatrensis (Sumatran fleabane) is considered a highly invasive and troublesome weed worldwide, including in European and Mediterranean regions. In Turkey, the use of glyphosate in orchards has recently increased; however, extensive use of glyphosate has resulted in poor control of C. sumatrensis in several peach orchards. The objectives of this research were to determine if C. sumatrensis is resistant to glyphosate and identify alternative herbicides with different modes of action that can be used instead of glyphosate. Two dose response studies were conducted in the greenhouse to evaluate the response of four C. sumatrensis populations to glyphosate, chlorsulfuron, and metribuzin. Glyphosate isopropyl amine and glyphosate potassium was applied at 0, 0.25, 0.5, 1, 2, 4, and 8 times the use rate of 1080 g a.e./ha (a.e. indicates acid equivalent) when the plants were at rosette (5-6 true leaves) and vegetative (20-22 cm tall) stages. Effects of both glyphosate formulations were combined. The resistant populations showed higher resistance 3.8 to 6.6 and 5.3 to 7.8 times at rosette stage and vegetative stage, respectively, compared with the susceptible population. Furthermore, glyphosate-resistant populations were treated with chlorsulfuron and metribuzin at 0, 0.25, 0.5, 1, 2, 4, and 8 times use rate of 7.5 and 350 g a.i./ha, respectively at the rosette stage. The glyphosate-resistant populations exhibited 2.4 to 3.8 times more resistance to chlorsulfuron, but were adequately controlled with metribuzin.

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Mechanisms of glyphosate resistance and response to alternative herbicide‐based management in populations of the three Conyza species introduced in southern Spain

Cited by 31 publications

References 47 publications

The First Case of Glyphosate Resistance in Johnsongrass (Sorghum halepense (L.) Pers.) in Europe

The First Case of Glyphosate Resistance in Johnsongrass (Sorghum halepense (L.) Pers.) in Europe

Does the Glyphosate Treatment Interfere Negatively on RNA Integrity in Glyphosate-Resistant and -Sensitive Conyza bonariensis?

Sumatran Fleabane (Conyza sumatrensis) Resistance to Glyphosate in Peach Orchards in Turkey

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