Lolium rigidum

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Stephen B. Powles - One of the best experts on this subject based on the ideXlab platform.

  • Diversity of α-tubulin transcripts in Lolium rigidum.
    Pest management science, 2020
    Co-Authors: Jinyi Chen, Heping Han, Zhizhan Chu, Eric L. Patterson, Stephen B. Powles
    Abstract:

    BACKGROUND Tubulin, the target site of dinitroaniline herbicides, is encoded by small gene families in plants. To better characterize the mechanisms of target-site resistance to dinitroaniline herbicides in the globally important weedy species Lolium rigidum, attempts were made to amplify and sequence α-tubulin transcripts. RESULTS Four α-tubulin isoforms (TUA1, TUA2, TUA3 and TUA4) were identified in L. rigidum. Variations in the number and sequence of transcripts encoding these α-tubulin proteins were found in individuals from the two L. rigidum populations examined. Within and among populations, differences in the 5'- and 3'-untranslated regions of cDNA in TUA3 and TUA4 were identified. Furthermore, a novel double mutation, Arg-390-Cys+Asp-442-Glu, in the TUA3 transcript was identified and has the potential to confer dinitroaniline resistance. CONCLUSION This research reveals the complexity of the α-tubulin gene family in individuals/populations of the cross-pollinated weedy species L. rigidum, and highlights the need for better understanding of the molecular architecture of tubulin gene families for detecting resistance point mutations. Although TUA4 is a commonly expressed α-tubulin isoform containing most frequently reported resistance mutations, other mutant tubulin isoforms may also have a role in conferring dinitroaniline resistance.

  • Metribuzin resistance via enhanced metabolism in a multiple herbicide resistant Lolium rigidum population
    Pest management science, 2020
    Co-Authors: Heping Han, Stephen B. Powles
    Abstract:

    BACKGROUND The photosystem II (PSII)-inhibiting herbicides are important for Australian farmers to control Lolium rigidum Gaud. and other weed species in trazine tolerant (TT)-canola fields. A L. rigidum population (R) collected from a TT-canola field from Western Australia showed multiple resistance to PSII, acetyl-coenzyme A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors. The mechanisms of multiple resistance in this R population were determined. RESULTS The R population showed a low-level (about 3.0-fold) resistance to the PSII-inhibiting herbicides metribuzin and atrazine. Sequencing of the psbA gene revealed no differences between the R and susceptible (S) sequences. Furthermore, [14 C]-metribuzin experiments found no significant difference in metribuzin foliar uptake and translocation between the R and S plants. However, [14 C]-metribuzin metabolism in R plants was 2.3-fold greater than in S plants. The cytochrome P450 monooxygenase inhibitor piperonyl butoxide (PBO) enhanced plant mortality response to metribuzin and atrazine in both R and S populations. In addition, multiple resistance to ALS and ACCase inhibitors are due to known resistance mutations in ALS and ACCase genes. CONCLUSION The results demonstrate that enhanced metribuzin metabolism likely involving cytochrome P450 monooxygenase contributes to metribuzin resistance in Lolium rigidum. This is the first report of metabolic resistance to the PSII-inhibiting herbicide metribuzin in Australian Lolium rigidum. © 2020 Society of Chemical Industry.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum.
    Journal of agricultural and food chemistry, 2018
    Co-Authors: Jinyi Chen, Heping Han, Roberto Busi, Danica E. Goggin, Stephen B. Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detec...

  • Pyroxasulfone resistance in Lolium rigidum is metabolism-based.
    Pesticide biochemistry and physiology, 2018
    Co-Authors: Roberto Busi, Aimone Porri, Todd A. Gaines, Stephen B. Powles
    Abstract:

    Abstract The evolution of resistant weed populations in response to intensive herbicide selection pressure is a global issue. Resistance to post-emergence herbicides is widespread, whereas soil-applied pre-emergence herbicides can often remain effective. For example, in Australia pyroxasulfone is a new pre-emergence soil-applied herbicide which provides control of Lolium rigidum populations resistant to multiple post-emergence herbicide modes of action. A fundamental knowledge of the genetic basis of metabolic resistance in weeds is important for understanding plant evolution pathways under herbicide selection and sustaining long-term weed resistance management. In this study we define the mechanistic basis of resistance to pyroxasulfone in a L. rigidum population. TLC provides evidence that pyroxasulfone resistance is metabolism-based with approximately 88% of parental [14C]-labelled pyroxasulfone metabolized in resistant plants 24 h after the herbicide treatment. HPLC-MS allowed identification of several metabolites of pyroxasulfone formed via a glutathione (GSH) conjugation pathway in pyroxasulfone-resistant L. rigidum plants. However, the initial pyroxasulfone-glutathione conjugate was not found likely due to its labile nature. The observed constitutive over-expression from six to nine-fold of two putative resistance-endowing GST genes was associated with the pyroxasulfone resistance phenotype. The most logical conclusion, based on the data thus far available, is that rapid detoxification of pyroxasulfone mediates pyroxasulfone resistance in L. rigidum plants. Future research is warranted to confirm the hypothesis advanced by this study of rapid pyroxasulfone metabolism due to GSH conjugation mediated by GST over-expressed in pyroxasulfone-resistant plants which similarly leads to the production of distinctive GSH-pyroxasulfone metabolites in L. rigidum and wheat.

  • Dinitroaniline herbicide resistance in a multiple-resistant Lolium rigidum population
    Pest management science, 2018
    Co-Authors: Jinyi Chen, Heping Han, Mechelle J. Owen, Stephen B. Powles
    Abstract:

    Background The pre-emergence dinitroaniline herbicides (such as trifluralin and pendimethalin) are vital to Australian no-till farming systems. A Lolium rigidum population collected from the Western Australian grain belt with a 12-year trifluralin use history was characterised for resistance to dinitroaniline, acetyl CoA carboxylase (ACCase)- and acetolactate synthase (ALS)-inhibiting herbicides. Target-site resistance mechanisms were investigated. Results This L. rigidum population exhibited 32-fold resistance to trifluralin, as compared with the susceptible population. It also displayed 12- to 30-fold cross-resistance to other dinitroaniline herbicides (pendimethalin, ethalfluralin and oryzalin). In addition, this population showed multiple resistance to commonly used post-emergence ACCase- and ALS-inhibiting herbicides. Two target-site α-tubulin gene mutations (Val-202-Phe and Thr-239-Ile) previously documented in other dinitroaniline-resistant weed species were identified, and some known target-site mutations in ACCase (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg) and ALS (Pro-197-Gln/Ser) were found in the same population. An agar-based Petri dish screening method was established for the rapid diagnosis of resistance to dinitroaniline herbicides. Conclusion Evolution of target-site resistance to both pre- and post-emergence herbicides was confirmed in a single L. rigidum population. The α-tubulin mutations Val-202-Phe and Thr-239-Ile, documented here for the first time in L. rigidum, are likely to be responsible for dinitroaniline resistance in this population. Early detection of dinitroaniline herbicide resistance and integrated weed management strategies are needed to maintain the effectiveness of dinitroaniline herbicides. © 2017 Society of Chemical Industry.

Roberto Busi - One of the best experts on this subject based on the ideXlab platform.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum.
    Journal of agricultural and food chemistry, 2018
    Co-Authors: Jinyi Chen, Heping Han, Roberto Busi, Danica E. Goggin, Stephen B. Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detec...

  • Pyroxasulfone resistance in Lolium rigidum is metabolism-based.
    Pesticide biochemistry and physiology, 2018
    Co-Authors: Roberto Busi, Aimone Porri, Todd A. Gaines, Stephen B. Powles
    Abstract:

    Abstract The evolution of resistant weed populations in response to intensive herbicide selection pressure is a global issue. Resistance to post-emergence herbicides is widespread, whereas soil-applied pre-emergence herbicides can often remain effective. For example, in Australia pyroxasulfone is a new pre-emergence soil-applied herbicide which provides control of Lolium rigidum populations resistant to multiple post-emergence herbicide modes of action. A fundamental knowledge of the genetic basis of metabolic resistance in weeds is important for understanding plant evolution pathways under herbicide selection and sustaining long-term weed resistance management. In this study we define the mechanistic basis of resistance to pyroxasulfone in a L. rigidum population. TLC provides evidence that pyroxasulfone resistance is metabolism-based with approximately 88% of parental [14C]-labelled pyroxasulfone metabolized in resistant plants 24 h after the herbicide treatment. HPLC-MS allowed identification of several metabolites of pyroxasulfone formed via a glutathione (GSH) conjugation pathway in pyroxasulfone-resistant L. rigidum plants. However, the initial pyroxasulfone-glutathione conjugate was not found likely due to its labile nature. The observed constitutive over-expression from six to nine-fold of two putative resistance-endowing GST genes was associated with the pyroxasulfone resistance phenotype. The most logical conclusion, based on the data thus far available, is that rapid detoxification of pyroxasulfone mediates pyroxasulfone resistance in L. rigidum plants. Future research is warranted to confirm the hypothesis advanced by this study of rapid pyroxasulfone metabolism due to GSH conjugation mediated by GST over-expressed in pyroxasulfone-resistant plants which similarly leads to the production of distinctive GSH-pyroxasulfone metabolites in L. rigidum and wheat.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum
    2018
    Co-Authors: Jinyi Chen, Roberto Busi, Heping Han, Danica Goggin, Stephen Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detection, overcoming the difficulties of quantifying this highly volatile herbicide by chromatographic methods

  • Pyroxasulfone resistance in Lolium rigidum conferred by enhanced metabolic capacity
    2017
    Co-Authors: Roberto Busi, Aimone Porri, Todd A. Gaines, Stephen B. Powles
    Abstract:

    The evolution of herbicide-resistant weed populations in response to synthetic herbicide selective pressure is threatening safe weed control practices achieved by these molecules. In Australia multiple-resistant populations of annual ryegrass (Lolium rigidum) are effectively controlled by soil-applied herbicides which provide adequate weed control. In this study we define the mechanistic basis of the experimentally-evolved resistance to the soil-applied herbicide pyroxasulfone in a L. rigidum population. TLC and HPLC-MS provide biochemical confirmation that pyroxasulfone resistance is metabolism-based with identification and quantification of pyroxasulfone metabolites formed via a glutathione conjugation pathway in pyroxasulfone-resistant L. rigidum plants. The observed over-expression of two putative resistance-endowing GST genes is consistent with pyroxasulfone-resistance in parental plants (P6) and positively correlated to pyroxasulfone resistance in F1 pair-cross progenies. Thus, a major detoxification mechanism involves glutathione conjugation to pyroxasulfone and GST over-expression in pyroxasulfone-resistant L. rigidum plants. The definition of the genetic basis of metabolic resistance in weeds can be a first crucial step towards chemical means to reverse resistance and improve long-term weed resistance management.

  • Phorate can reverse P450 metabolism-based herbicide resistance in Lolium rigidum.
    Pest management science, 2016
    Co-Authors: Roberto Busi, Todd A. Gaines, Stephen B. Powles
    Abstract:

    BACKGROUND Organophosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms, leading to synergistic interactions between the insecticide and the herbicide. In this study we report synergistic versus antagonistic interactions between the organophosphate insecticide phorate and five different herbicides observed in a population of multiple herbicide-resistant Lolium rigidum. RESULTS Phorate synergised with three different herbicide modes of action, enhancing the activity of the ALS inhibitor chlorsulfuron (60% LD50 reduction), the VLCFAE inhibitor pyroxasulfone (45% LD50 reduction) and the mitosis inhibitor trifluralin (70% LD50 reduction). Conversely, phorate antagonised the two thiocarbamate herbicides prosulfocarb and triallate with a 12-fold LD50 increase. CONCLUSION We report the selective reversal of P450-mediated metabolic multiple resistance to chlorsulfuron and trifluralin in the grass weed L. rigidum by synergistic interaction with the insecticide phorate, and discuss the putative mechanistic basis. This research should encourage diversity in herbicide use patterns for weed control as part of a long-term integrated management effort to reduce the risk of selection of metabolism-based multiple herbicide resistance in L. rigidum. © 2016 Society of Chemical Industry

Christopher Preston - One of the best experts on this subject based on the ideXlab platform.

  • Resistance to Multiple PRE Herbicides in a Field-Evolved Rigid Ryegrass (Lolium rigidum) Population
    Weed Science, 2018
    Co-Authors: David J. Brunton, Peter Boutsalis, Gurjeet Gill, Christopher Preston
    Abstract:

    A population of rigid ryegrass (Lolium rigidum Gaudin) from a field on the Eyre Peninsula, South Australia, was suspected of resistance to thiocarbamate herbicides. Dose–response studies were conducted on this population (EP162) and two susceptible populations (SLR4 and VLR1). The resistant population exhibited cross-resistance to triallate, prosulfocarb, EPTC, and thiobencarb with higher LD50 to triallate (14.9-fold), prosulfocarb (9.4-fold), EPTC (9.7-fold), and thiobencarb (13.6-fold) compared with the susceptible populations SLR4 and VLR1. The resistant population also displayed resistance to trifluralin, pyroxasulfone, and propyzamide. The LD50 of the resistant population was higher for trifluralin (13.8-fold), pyroxasulfone (8.1-fold), and propyzamide (2.7-fold) compared with the susceptible populations. This study documents the first case of field-evolved resistance to thiocarbamate herbicides in L. rigidum.

  • Inheritance of evolved clethodim resistance in Lolium rigidum populations from Australia.
    Pest management science, 2017
    Co-Authors: Rupinder Kaur Saini, Gurjeet Gill, Jenna Malone, Christopher Preston
    Abstract:

    BACKGROUND In Australia, the extensive use of clethodim for the control of Lolium rigidum has resulted in the evolution of many clethodim-resistant L. rigidum populations. Five clethodim-resistant populations of L. rigidum were analysed for the inheritance of clethodim resistance. RESULTS Reciprocal crosses were made between resistant (R) and susceptible (S) populations. Within crosses, dose–responses of reciprocal F1 families of all populations except A61 were similar to each other, indicating that clethodim resistance in these populations is encoded on the nuclear genome. The level of dominance observed in the dose–response experiments ranged from partial to complete within the herbicide rate used. In the A61 population, within each cross, the response of F1 from the maternal and paternal parent was different, indicating that resistance is inherited through the female parent. All backcross populations segregated in a different manner. Only one population, FP, fitted a single-gene model (1:1). Two populations fitted two-gene models: a 3:1 inheritance model for F4 and a 1:3 inheritance model for A91. For population E2, no clear pattern of inheritance was determined, suggesting more complex inheritance. CONCLUSION The results of this study indicate that different patterns of clethodim resistance in L. rigidum exist. © 2016 Society of Chemical Industry

  • New mode of action herbicides to combat herbicide resistant annual ryegrass (Lolium rigidum) in Australian cereal production
    2010
    Co-Authors: Peter Boutsalis, Gurjeet Gill, Christopher Preston, S. M. Zydenbos
    Abstract:

    Summary Herbicide resistance in annual ryegrass across southern Australia is currently a major issue for grain producers. Currently annual ryegrass (Lolium rigidum Gaudin) has evolved resistance to all post-emergent herbicides that can be used to control it in cereal crops and to the pre-emergent herbicide trifluralin. No new herbicide modes of action for the control of annual ryegrass have been marketed since the 1980s. In the past 5 years, research has been conducted with new mode of action herbicides that are selective in cereals. Prosulfocarb + S-metolachlor and pyroxasulfone effectively controlled 20 trifluralinresistant populations of annual ryegrass in pot trials. Field trials have determined that prosulfocarb + S-metolachlor, pyroxasulfone and dimethenamid-P could control trifluralin-resistant annual ryegrass when applied and incorporated by sowing (IBS) in the field. Prosulfocarb + S-metolachlor and pyroxasulfone were safe in barley, but dimethenamid-P caused unacceptable damage. Improved control of annual ryegrass was achieved by splitting the herbicide application between IBS and post-sow, pre-emergent (PSPE).

  • Spread of herbicide resistance alleles in Lolium rigidum Gaud. (annual ryegrass).
    2010
    Co-Authors: Jenna Malone, Peter Boutsalis, Christopher Preston, S. M. Zydenbos
    Abstract:

    Herbicide resistant weeds are a major problem in grain cropping areas of southern Australia. Resistance to the acetyl-coenzyme A carboxylase inhibiting herbicides is widespread in this area. In order to better understand how resistance to ACCaseinhibiting herbicides in populations of Lolium rigidum in South Australia has changed with time, the carboxyl-transferase (CT) domain of the ACCase gene from resistant L. rigidum populations collected in random surveys over 10 years was sequenced and mutations that cause resistance characterised. Mutations were identified in more than 80% of resistant individuals, indicating target site mutation is the most common mechanism of resistance in L. rigidum to this herbicide mode of action. Mutations at seven previously characterised positions in the ACCase gene were identified, and individuals containing multiple mutations were also found. Mutations at position 2041 occurred at the highest frequency in all years. However, other mutations and individuals carrying two mutations have increased in frequency. This study has shown that target site resistance to ACCase-inhibiting herbicides in L. rigidum is widespread across South Australia and has evolved numerous times.

  • Impact of management on glyphosate-resistant Lolium rigidum populations on farm.
    2008
    Co-Authors: A. M. Wakelin, Christopher Preston
    Abstract:

    Glyphosate resistance in Lolium rigidum Gaudin has appeared in 64 known locations across Australia since 1996. A variety of management strategies have been suggested for managing glyphosate-resistant L. rigidum; however, there is no surety that these strategies will reduce the impact of glyphosate-resistant weeds in all situations. A survey was conducted to determine the impact of management on glyphosate-resistant L. rigidum populations in the field. Populations were successively sampled from fields with glyphosate-resistant L. rigidum and tested for resistance to glyphosate. The percentage of the population resistant to glyphosate decreased at two sites where glyphosate was not used alone for weed control. At the third site, where glyphosate was the only effective herbicide, the percentage of resistant individuals increased. With intensive management it is possible to reduce glyphosate resistance to low levels.

Heping Han - One of the best experts on this subject based on the ideXlab platform.

  • Diversity of α-tubulin transcripts in Lolium rigidum.
    Pest management science, 2020
    Co-Authors: Jinyi Chen, Heping Han, Zhizhan Chu, Eric L. Patterson, Stephen B. Powles
    Abstract:

    BACKGROUND Tubulin, the target site of dinitroaniline herbicides, is encoded by small gene families in plants. To better characterize the mechanisms of target-site resistance to dinitroaniline herbicides in the globally important weedy species Lolium rigidum, attempts were made to amplify and sequence α-tubulin transcripts. RESULTS Four α-tubulin isoforms (TUA1, TUA2, TUA3 and TUA4) were identified in L. rigidum. Variations in the number and sequence of transcripts encoding these α-tubulin proteins were found in individuals from the two L. rigidum populations examined. Within and among populations, differences in the 5'- and 3'-untranslated regions of cDNA in TUA3 and TUA4 were identified. Furthermore, a novel double mutation, Arg-390-Cys+Asp-442-Glu, in the TUA3 transcript was identified and has the potential to confer dinitroaniline resistance. CONCLUSION This research reveals the complexity of the α-tubulin gene family in individuals/populations of the cross-pollinated weedy species L. rigidum, and highlights the need for better understanding of the molecular architecture of tubulin gene families for detecting resistance point mutations. Although TUA4 is a commonly expressed α-tubulin isoform containing most frequently reported resistance mutations, other mutant tubulin isoforms may also have a role in conferring dinitroaniline resistance.

  • Metribuzin resistance via enhanced metabolism in a multiple herbicide resistant Lolium rigidum population
    Pest management science, 2020
    Co-Authors: Heping Han, Stephen B. Powles
    Abstract:

    BACKGROUND The photosystem II (PSII)-inhibiting herbicides are important for Australian farmers to control Lolium rigidum Gaud. and other weed species in trazine tolerant (TT)-canola fields. A L. rigidum population (R) collected from a TT-canola field from Western Australia showed multiple resistance to PSII, acetyl-coenzyme A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors. The mechanisms of multiple resistance in this R population were determined. RESULTS The R population showed a low-level (about 3.0-fold) resistance to the PSII-inhibiting herbicides metribuzin and atrazine. Sequencing of the psbA gene revealed no differences between the R and susceptible (S) sequences. Furthermore, [14 C]-metribuzin experiments found no significant difference in metribuzin foliar uptake and translocation between the R and S plants. However, [14 C]-metribuzin metabolism in R plants was 2.3-fold greater than in S plants. The cytochrome P450 monooxygenase inhibitor piperonyl butoxide (PBO) enhanced plant mortality response to metribuzin and atrazine in both R and S populations. In addition, multiple resistance to ALS and ACCase inhibitors are due to known resistance mutations in ALS and ACCase genes. CONCLUSION The results demonstrate that enhanced metribuzin metabolism likely involving cytochrome P450 monooxygenase contributes to metribuzin resistance in Lolium rigidum. This is the first report of metabolic resistance to the PSII-inhibiting herbicide metribuzin in Australian Lolium rigidum. © 2020 Society of Chemical Industry.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum.
    Journal of agricultural and food chemistry, 2018
    Co-Authors: Jinyi Chen, Heping Han, Roberto Busi, Danica E. Goggin, Stephen B. Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detec...

  • Dinitroaniline herbicide resistance in a multiple-resistant Lolium rigidum population
    Pest management science, 2018
    Co-Authors: Jinyi Chen, Heping Han, Mechelle J. Owen, Stephen B. Powles
    Abstract:

    Background The pre-emergence dinitroaniline herbicides (such as trifluralin and pendimethalin) are vital to Australian no-till farming systems. A Lolium rigidum population collected from the Western Australian grain belt with a 12-year trifluralin use history was characterised for resistance to dinitroaniline, acetyl CoA carboxylase (ACCase)- and acetolactate synthase (ALS)-inhibiting herbicides. Target-site resistance mechanisms were investigated. Results This L. rigidum population exhibited 32-fold resistance to trifluralin, as compared with the susceptible population. It also displayed 12- to 30-fold cross-resistance to other dinitroaniline herbicides (pendimethalin, ethalfluralin and oryzalin). In addition, this population showed multiple resistance to commonly used post-emergence ACCase- and ALS-inhibiting herbicides. Two target-site α-tubulin gene mutations (Val-202-Phe and Thr-239-Ile) previously documented in other dinitroaniline-resistant weed species were identified, and some known target-site mutations in ACCase (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg) and ALS (Pro-197-Gln/Ser) were found in the same population. An agar-based Petri dish screening method was established for the rapid diagnosis of resistance to dinitroaniline herbicides. Conclusion Evolution of target-site resistance to both pre- and post-emergence herbicides was confirmed in a single L. rigidum population. The α-tubulin mutations Val-202-Phe and Thr-239-Ile, documented here for the first time in L. rigidum, are likely to be responsible for dinitroaniline resistance in this population. Early detection of dinitroaniline herbicide resistance and integrated weed management strategies are needed to maintain the effectiveness of dinitroaniline herbicides. © 2017 Society of Chemical Industry.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum
    2018
    Co-Authors: Jinyi Chen, Roberto Busi, Heping Han, Danica Goggin, Stephen Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detection, overcoming the difficulties of quantifying this highly volatile herbicide by chromatographic methods

Jinyi Chen - One of the best experts on this subject based on the ideXlab platform.

  • Diversity of α-tubulin transcripts in Lolium rigidum.
    Pest management science, 2020
    Co-Authors: Jinyi Chen, Heping Han, Zhizhan Chu, Eric L. Patterson, Stephen B. Powles
    Abstract:

    BACKGROUND Tubulin, the target site of dinitroaniline herbicides, is encoded by small gene families in plants. To better characterize the mechanisms of target-site resistance to dinitroaniline herbicides in the globally important weedy species Lolium rigidum, attempts were made to amplify and sequence α-tubulin transcripts. RESULTS Four α-tubulin isoforms (TUA1, TUA2, TUA3 and TUA4) were identified in L. rigidum. Variations in the number and sequence of transcripts encoding these α-tubulin proteins were found in individuals from the two L. rigidum populations examined. Within and among populations, differences in the 5'- and 3'-untranslated regions of cDNA in TUA3 and TUA4 were identified. Furthermore, a novel double mutation, Arg-390-Cys+Asp-442-Glu, in the TUA3 transcript was identified and has the potential to confer dinitroaniline resistance. CONCLUSION This research reveals the complexity of the α-tubulin gene family in individuals/populations of the cross-pollinated weedy species L. rigidum, and highlights the need for better understanding of the molecular architecture of tubulin gene families for detecting resistance point mutations. Although TUA4 is a commonly expressed α-tubulin isoform containing most frequently reported resistance mutations, other mutant tubulin isoforms may also have a role in conferring dinitroaniline resistance.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum.
    Journal of agricultural and food chemistry, 2018
    Co-Authors: Jinyi Chen, Heping Han, Roberto Busi, Danica E. Goggin, Stephen B. Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detec...

  • Dinitroaniline herbicide resistance in a multiple-resistant Lolium rigidum population
    Pest management science, 2018
    Co-Authors: Jinyi Chen, Heping Han, Mechelle J. Owen, Stephen B. Powles
    Abstract:

    Background The pre-emergence dinitroaniline herbicides (such as trifluralin and pendimethalin) are vital to Australian no-till farming systems. A Lolium rigidum population collected from the Western Australian grain belt with a 12-year trifluralin use history was characterised for resistance to dinitroaniline, acetyl CoA carboxylase (ACCase)- and acetolactate synthase (ALS)-inhibiting herbicides. Target-site resistance mechanisms were investigated. Results This L. rigidum population exhibited 32-fold resistance to trifluralin, as compared with the susceptible population. It also displayed 12- to 30-fold cross-resistance to other dinitroaniline herbicides (pendimethalin, ethalfluralin and oryzalin). In addition, this population showed multiple resistance to commonly used post-emergence ACCase- and ALS-inhibiting herbicides. Two target-site α-tubulin gene mutations (Val-202-Phe and Thr-239-Ile) previously documented in other dinitroaniline-resistant weed species were identified, and some known target-site mutations in ACCase (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg) and ALS (Pro-197-Gln/Ser) were found in the same population. An agar-based Petri dish screening method was established for the rapid diagnosis of resistance to dinitroaniline herbicides. Conclusion Evolution of target-site resistance to both pre- and post-emergence herbicides was confirmed in a single L. rigidum population. The α-tubulin mutations Val-202-Phe and Thr-239-Ile, documented here for the first time in L. rigidum, are likely to be responsible for dinitroaniline resistance in this population. Early detection of dinitroaniline herbicide resistance and integrated weed management strategies are needed to maintain the effectiveness of dinitroaniline herbicides. © 2017 Society of Chemical Industry.

  • Enhanced Trifluralin Metabolism Can Confer Resistance in Lolium rigidum
    2018
    Co-Authors: Jinyi Chen, Roberto Busi, Heping Han, Danica Goggin, Stephen Powles
    Abstract:

    Resistance to the pre-emergence herbicide trifluralin is increasing in Australian annual ryegrass (Lolium rigidum) populations. Three L. rigidum populations (R1, R2, and R3) collected from Australian grain fields were identified with trifluralin resistance. Both target-site and nontarget-site resistance mechanisms were investigated. No target-site α-tubulin mutations were detected in populations R1 and R3, while an Arg-243-Lys mutation was found in R2. Compared with the three trifluralin-susceptible populations, enhanced [14C]-trifluralin metabolism, quantified by measuring the amount of [14C] label partitioning into the polar phase of a hexane:methanol system, was identified in all the three resistant populations. This is the first report of metabolic resistance to trifluralin. Coevolution of target-site and nontarget-site resistance to trifluralin is occurring, and metabolic resistance is not rare in L. rigidum populations in Australia. A method was established for trifluralin metabolic resistance detection, overcoming the difficulties of quantifying this highly volatile herbicide by chromatographic methods

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