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Krenchinski FH, Costa RN, Pereira VGC, Bevilaqua NC, Alcántara-de la Cruz R, Velini ED, Carbonari CA. Glyphosate hormesis induced by treatment via seed stimulates the growth and biomass accumulation in soybean seedlings. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170387. [PMID: 38280604 DOI: 10.1016/j.scitotenv.2024.170387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 01/17/2024] [Accepted: 01/21/2024] [Indexed: 01/29/2024]
Abstract
Glyphosate hormesis, identified as a potential means to enhance crop yields, encounters practical constraints because it is typically assessed through foliar applications. The expression and extend of hormesis in this approach are influenced by unpredictable environmental conditions, highlighting the need to explore alternative glyphosate application methods, such as seed treatment. This study aimed to assess glyphosate hormesis on growth rates and biomass accumulation in seedlings soybean cultivars. Two dose-response experiments [doses from 0 to 2880 g acid equivalent (ae) ha-1], one via foliar and one via seed, were conducted on three soybean cultivars [one non-glyphosate-resistant (NGR) and two glyphosate-resistant (GR, one RR and one RR2)]. In a subsequent experiment, three safe glyphosate doses (0, 90 and 180 g ae ha-1) applied via seed were evaluated on four soybean cultivars (two RR and two RR2). For foliar applications, the range of glyphosate doses increasing growth rates and dry biomass by 12-28 % were 5.6-45 g ae ha-1 for the NGR cultivar, of 45-720 g ae ha-1 for RR and of 11.25-180 g ae ha-1 for RR2. In the seed treatment, biomass increases of 16-60 % occurred at 45-180 g ae ha-1 for the NGR and RR cultivars, and 90-360 g ae ha-1 for RR2. Glyphosate doses of 90 and 180 g ae ha-1, applied via seeds, provided greater growth and biomass accumulation for the RR and RR2 soybean cultivars. Both foliar and seed applications of glyphosate increased growth and biomass accumulation in soybean cultivars, with seed treatments showing greater and more consistent enhancements. These findings propose practical and viable alternative for harnessing glyphosate hormesis to facilitate the early development of soybeans and potentially enhance crop yield.
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Affiliation(s)
- Fábio Henrique Krenchinski
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil
| | - Renato Nunes Costa
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil
| | - Vinicius Gabriel Canepelle Pereira
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil
| | - Natália Cunha Bevilaqua
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil
| | - Ricardo Alcántara-de la Cruz
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil.
| | - Edivaldo D Velini
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil
| | - Caio A Carbonari
- Center for Advanced Research in Weed Science, Department of Plant Protection, College of Agricultural Sciences, São Paulo State University, 18610-034 Botucatu, Brazil
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Singh R, Shukla A, Kaur G, Girdhar M, Malik T, Mohan A. Systemic Analysis of Glyphosate Impact on Environment and Human Health. ACS OMEGA 2024; 9:6165-6183. [PMID: 38371781 PMCID: PMC10870391 DOI: 10.1021/acsomega.3c08080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/15/2023] [Accepted: 12/29/2023] [Indexed: 02/20/2024]
Abstract
With a growing global population, agricultural scientists are focusing on crop production management and the creation of new strategies for a higher agricultural output. However, the growth of undesirable plants besides the primary crop poses a significant challenge in agriculture, necessitating the massive application of herbicides to eradicate this problem. Several synthetic herbicides are widely utilized, with glyphosate emerging as a potential molecule for solving this emerging issue; however, it has several environmental and health consequences. Several weed species have evolved resistance to this herbicide, therefore lowering agricultural yield. The persistence of glyphosate residue in the environment, such as in water and soil systems, is due to the misuse of glyphosate in agricultural regions, which causes its percolation into groundwater via the vertical soil profile. As a result, it endangers many nontarget organisms existing in the natural environment, which comprises both soil and water. The current Review aims to provide a systemic analysis of glyphosate, its various effects on the environment, its subsequent impact on human health and animals, which will lead us toward a better understanding of the issues about herbicide usage and aid in managing it wisely, as in the near the future glyphosate market is aiming for a positive forecast until 2035.
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Affiliation(s)
- Reenu Singh
- School
of Bioengineering and Biosciences, Lovely
Professional University, Phagwara, Punjab 144411, India
| | - Akanksha Shukla
- School
of Bioengineering and Biosciences, Lovely
Professional University, Phagwara, Punjab 144411, India
| | - Gurdeep Kaur
- School
of Chemical Engineering and Physical Sciences, Lovely Professional University, Phagwara, Punjab 144411, India
| | - Madhuri Girdhar
- School
of Bioengineering and Biosciences, Lovely
Professional University, Phagwara, Punjab 144411, India
| | - Tabarak Malik
- Department
of Biomedical Sciences, Institute of Health, Jimma University, Jimma 00000, Ethiopia
| | - Anand Mohan
- School
of Bioengineering and Biosciences, Lovely
Professional University, Phagwara, Punjab 144411, India
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3
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Duke SO, Pan Z, Bajsa-Hirschel J, Tamang P, Hammerschmidt R, Lorsbach BA, Sparks TC. Molecular Targets of Herbicides and Fungicides─Are There Useful Overlaps for Fungicide Discovery? JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:20532-20548. [PMID: 38100716 PMCID: PMC10755756 DOI: 10.1021/acs.jafc.3c07166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/17/2023]
Abstract
New fungicide modes of action are needed for fungicide resistance management strategies. Several commercial herbicide targets found in fungi that are not utilized by commercial fungicides are discussed as possible fungicide molecular targets. These are acetyl CoA carboxylase, acetolactate synthase, 5-enolpyruvylshikimate-3-phosphate synthase, glutamine synthase, phytoene desaturase, protoporphyrinogen oxidase, long-chain fatty acid synthase, dihydropteroate synthase, hydroxyphenyl pyruvate dioxygenase, and Ser/Thr protein phosphatase. Some of the inhibitors of these herbicide targets appear to be either good fungicides or good leads for new fungicides. For example, some acetolactate synthase and dihydropteroate inhibitors are excellent fungicides. There is evidence that some herbicides have indirect benefits to certain crops due to their effects on fungal crop pathogens. Using a pesticide with both herbicide and fungicide activities based on the same molecular target could reduce the total amount of pesticide used. The limitations of such a product are discussed.
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Affiliation(s)
- Stephen O. Duke
- National
Center for Natural Products Research, School of Pharmacy, University of Mississippi, University 38667, United States
| | - Zhiqiang Pan
- Natural
Products Utilization Research Unit, United
States Department of Agriculture, University 38667, United States
| | - Joanna Bajsa-Hirschel
- Natural
Products Utilization Research Unit, United
States Department of Agriculture, University 38667, United States
| | - Prabin Tamang
- Natural
Products Utilization Research Unit, United
States Department of Agriculture, University 38667, United States
| | - Raymond Hammerschmidt
- Department
of Plant, Soil and Microbial Sciences, Michigan
State University, East Lansing, Michigan 48824, United States
| | - Beth A. Lorsbach
- Nufarm, 4020 Aerial Center Parkway, Morrisville, North Carolina 27560, United States
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4
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Akbarabadi A, Ismaili A, Nazarian Firouzabadi F, Ercisli S, Kahrizi D. Assessment of ACC and P450 Genes Expression in Wild Oat (Avena ludoviciana) in Different Tissues Under Herbicide Application. Biochem Genet 2023; 61:1867-1879. [PMID: 36877417 DOI: 10.1007/s10528-023-10357-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 02/15/2023] [Indexed: 03/07/2023]
Abstract
Target-site resistance (TSR) and non-target-site resistance (NTSR) to herbicides in arable weeds are increasing rapidly all over the world and threatening universal food safety. Resistance to herbicides that inhibit ACCase activity has been identified in wild oat. In this study, expression of ACC1, ACC2, CYP71R4 and CYP81B1 genes under herbicide stress conditions were studied in two TSR (resistant in the residue Ile1781-Leu and Ile2041-Asn of ACCase) biotypes, two NTSR biotypes and one susceptible biotype of A. ludoviciana for the first time. Treated and untreated biotypes with ACCase-inhibitor clodinafop propargyl herbicide were sampled from the stem and leaf tissues at 24 h after treatment. Our results showed an increase in gene expression levels in different tissues of both types of resistance biotypes that occurred under herbicide treatment compared with non-herbicide treatment. In all samples, the expression levels of leaf tissue in all studied genes were higher than in stem tissue. The results of ACC gene expression showed that the expression level of ACC1 was significantly higher than that of ACC2. Also, expression levels of TSR biotypes were higher than NTSR biotypes for the ACC1 gene. For both CYP71R4 and CYP81B1 genes, the expression ratio increased significantly in TSR and NTSR biotypes in different tissues after herbicide treatment. In contrast, the expression levels of CYP genes in NTSR biotypes were higher than in TSR biotypes. Our results support the hypothesis that the reaction of plants to herbicide is carried out through a different regulation of genes, which can be the result of the interaction of resistance type in the target or non-target-site.
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Affiliation(s)
- Ali Akbarabadi
- Department of Plant Production and Genetic Engineering, Faculty of Agriculture, Lorestan University, Khorramabad, Iran
| | - Ahmad Ismaili
- Department of Plant Production and Genetic Engineering, Faculty of Agriculture, Lorestan University, Khorramabad, Iran
| | - Farhad Nazarian Firouzabadi
- Department of Plant Production and Genetic Engineering, Faculty of Agriculture, Lorestan University, Khorramabad, Iran
| | - Sezai Ercisli
- Department of Horticulture, Faculty of Agriculture, Ataturk University, 25240, Erzurum, Turkey
| | - Danial Kahrizi
- Department of Biotechnology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
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Vennapusa AR, Agarwal S, Rao Hm H, Aarthy T, Babitha KC, Thulasiram HV, Kulkarni MJ, Melmaiee K, Sudhakar C, Udayakumar M, S Vemanna R. Stacking herbicide detoxification and resistant genes improves glyphosate tolerance and reduces phytotoxicity in tobacco (Nicotiana tabacum L.) and rice (Oryza sativa L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 189:126-138. [PMID: 36084528 DOI: 10.1016/j.plaphy.2022.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/15/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Glyphosate residues retained in the growing meristematic tissues or in grains of glyphosate-resistant crops affect the plants physiological functions and crop yield. Removing glyphosate residues in the plants is desirable with no penalty on crop yield and quality. We report a new combination of scientific strategy to detoxify glyphosate that reduces the residual levels and improve crop resistance. The glyphosate detoxifying enzymes Aldo-keto reductase (AKR1) and mutated glycine oxidase (mGO) with different modes of action were co-expressed with modified EPSPS, which is insensitive to glyphosate in tobacco (Nicotiana tabacum L.) and rice (Oryza sativa L.). The transgenic tobacco plants expressing individual PsAKR1, mGO, CP4-EPSPS, combinations of PsAKR1:CP4EPSPS, PsAKR1:mGO, and multigene with PsAKR1: mGO: CP4EPSPS genes were developed. The bio-efficacy studies of in-vitro leaf regeneration on different concentrations of glyphosate, seedling bioassay, and spray on transgenic tobacco plants demonstrate that glyphosate detoxification with enhanced resistance. Comparative analysis of the transgenic tobacco plants reveals that double and multigene expressing transgenics had reduced accumulation of shikimic acid, glyphosate, and its primary residue AMPA, and increased levels of sarcosine were observed in all PsAKR1 expressing transgenics. The multigene expressing rice transgenics showed improved glyphosate resistance with yield maintenance. In summary, results suggest that stacking genes with two different detoxification mechanisms and insensitive EPSPS is a potential approach for developing glyphosate-resistant plants with less residual content.
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Affiliation(s)
- Amaranatha Reddy Vennapusa
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bangalore, 560065, India; Department of Botany, Sri Krishnadevaraya University, Anantapur, 515001, India; Department of Agriculture and Natural Resources, Delaware State University, Dover, DE, 19901, USA.
| | - Subham Agarwal
- Laboratory of Plant Functional Genomics, Regional Center for Biotechnology, Faridabad, 121001, India
| | - Hanumanth Rao Hm
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bangalore, 560065, India
| | | | - K C Babitha
- Laboratory of Plant Functional Genomics, Regional Center for Biotechnology, Faridabad, 121001, India
| | | | | | - Kalpalatha Melmaiee
- Department of Agriculture and Natural Resources, Delaware State University, Dover, DE, 19901, USA
| | - Chinta Sudhakar
- Department of Botany, Sri Krishnadevaraya University, Anantapur, 515001, India
| | - M Udayakumar
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bangalore, 560065, India
| | - Ramu S Vemanna
- Laboratory of Plant Functional Genomics, Regional Center for Biotechnology, Faridabad, 121001, India.
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6
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Duke SO, Dayan FE. The search for new herbicide mechanisms of action: Is there a 'holy grail'? PEST MANAGEMENT SCIENCE 2022; 78:1303-1313. [PMID: 34796620 DOI: 10.1002/ps.6726] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/18/2021] [Indexed: 05/26/2023]
Abstract
New herbicide modes of action (MOAs) are in great demand because of the burgeoning evolution of resistance of weeds to existing commercial herbicides. This need has been exacerbated by the almost complete lack of introduction of herbicides with new MOAs for almost 40 years. There are many highly phytotoxic compounds with MOAs not represented by commercial herbicides, but neither these compounds nor structural analogues have been developed as herbicides for a variety of reasons. Natural products provide knowledge of many MOAs that are not being utilized by commercial herbicides. Other means of identifying new herbicide targets are discussed, including pharmaceutical target sites and metabolomic and proteomic information, as well as the use of artificial intelligence and machine learning to predict herbicidal compounds with new MOAs. Information about several newly discovered herbicidal compounds with new MOAs is summarized. The currently increased efforts of both established companies and start-up companies are likely to result in herbicides with new MOAs that can be used in herbicide resistance management within the next decade. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Oxford, MS, USA
| | - Franck E Dayan
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, USA
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7
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Mehta S, Kumar A, Achary VMM, Ganesan P, Rathi N, Singh A, Sahu KP, Lal SK, Das TK, Reddy MK. Antifungal activity of glyphosate against fungal blast disease on glyphosate-tolerant OsmEPSPS transgenic rice. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 311:111009. [PMID: 34482912 DOI: 10.1016/j.plantsci.2021.111009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/20/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Weeds, pests, and pathogens are among the pre-harvest constraints in rice farming across rice-growing countries. For weed management, manual weeding and herbicides are widely practiced. Among the herbicides, glyphosate [N-(phosphonomethyl) glycine] is a broad-spectrum systemic chemical extensively used in agriculture. Being a competitive structural analog to phosphoenolpyruvate, it selectively inhibits the conserved 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme required for the biosynthesis of aromatic amino acids and essential metabolites in eukaryotes and prokaryotes. In the present study, we investigated the antifungal and defense elicitor activity of glyphosate against Magnaporthe oryzae on transgenic-rice overexpressing a glyphosate-resistance OsEPSPS gene (T173I + P177S; TIPS OsmEPSPS) for blast disease management. The glyphosate foliar spray on OsmEPSPS transgenic rice lines showed both prophylactic and curative suppression of blast disease comparable to a blasticide, tricyclazole. The glyphosate displayed direct antifungal activity on Magnaporthe oryzae as well as enhanced the levels of antioxidant enzymes and photosynthetic pigments in rice. However, the genes associated with phytohormones-mediated defense (OsPAD4, OsNPR1.3, and OsFMO) and innate immunity pathway (OsCEBiP and OsCERK1) were found repressed upon glyphosate spray. Altogether, the current study is the first report highlighting the overexpression of a crop-specific TIPS mutation in conjugation with glyphosate application showing potential for blast disease management in rice cultivation.
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Affiliation(s)
- Sahil Mehta
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Aundy Kumar
- ICAR-Indian Agricultural Research Institute, New Delhi, India.
| | - V Mohan Murali Achary
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Prakash Ganesan
- ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Neelmani Rathi
- ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Asmita Singh
- ICAR-Indian Agricultural Research Institute, New Delhi, India
| | | | - Shambhu Krishan Lal
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India; ICAR-Indian Institute of Agricultural Biotechnology, Ranchi, Jharkhand, India
| | - T K Das
- ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Malireddy K Reddy
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
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8
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Rodríguez-Gil JL, Prosser RS, Duke SO, Solomon KR. Ecotoxicology of Glyphosate, Its Formulants, and Environmental Degradation Products. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 255:129-205. [PMID: 34104986 DOI: 10.1007/398_2020_56] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The chemical and biological properties of glyphosate are key to understanding its fate in the environment and potential risks to non-target organisms. Glyphosate is polar and water soluble and therefore does not bioaccumulate, biomagnify, or accumulate to high levels in the environment. It sorbs strongly to particles in soil and sediments and this reduces bioavailability so that exposures to non-target organisms in the environment are acute and decrease with half-lives in the order of hours to a few days. The target site for glyphosate is not known to be expressed in animals, which reduces the probability of toxicity and small risks. Technical glyphosate (acid or salts) is of low to moderate toxicity; however, when mixed with some formulants such as polyoxyethylene amines (POEAs), toxicity to aquatic animals increases about 15-fold on average. However, glyphosate and the formulants have different fates in the environment and they do not necessarily co-occur. Therefore, toxicity tests on formulated products in scenarios where they would not be used are unrealistic and of limited use for assessment of risk. Concentrations of glyphosate in surface water are generally low with minimal risk to aquatic organisms, including plants. Toxicity and risks to non-target terrestrial organisms other than plants treated directly are low and risks to terrestrial invertebrates and microbial processes in soil are very small. Formulations containing POEAs are not labeled for use over water but, because POEA rapidly partitions into sediment, risks to aquatic organisms from accidental over-sprays are reduced in shallow water bodies. We conclude that use of formulations of glyphosate under good agricultural practices presents a de minimis risk of direct and indirect adverse effects in non-target organisms.
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Affiliation(s)
- Jose Luis Rodríguez-Gil
- IISD - Experimental Lakes Area, Winnipeg, MB, Canada.
- Department of Environment and Geography, University of Manitoba, Winnipeg, MB, Canada.
| | - Ryan S Prosser
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, MS, USA
| | - Keith R Solomon
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
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9
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Duke SO. Glyphosate: Uses Other Than in Glyphosate-Resistant Crops, Mode of Action, Degradation in Plants, and Effects on Non-target Plants and Agricultural Microbes. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 255:1-65. [PMID: 33895876 DOI: 10.1007/398_2020_53] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Glyphosate is the most used herbicide globally. It is a unique non-selective herbicide with a mode of action that is ideal for vegetation management in both agricultural and non-agricultural settings. Its use was more than doubled by the introduction of transgenic, glyphosate-resistant (GR) crops. All of its phytotoxic effects are the result of inhibition of only 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), but inhibition of this single enzyme of the shikimate pathway results in multiple phytotoxicity effects, both upstream and downstream from EPSPS, including loss of plant defenses against pathogens. Degradation of glyphosate in plants and microbes is predominantly by a glyphosate oxidoreductase to produce aminomethylphosphonic acid and glyoxylate and to a lesser extent by a C-P lyase to produce sarcosine and phosphate. Its effects on non-target plant species are generally less than that of many other herbicides, as it is not volatile and is generally sprayed in larger droplet sizes with a relatively low propensity to drift and is inactivated by tight binding to most soils. Some microbes, including fungal plant pathogens, have glyphosate-sensitive EPSPS. Thus, glyphosate can benefit GR crops by its activity on some plant pathogens. On the other hand, glyphosate can adversely affect some microbes that are beneficial to agriculture, such as Bradyrhizobium species, although GR crop yield data indicate that such an effect has been minor. Effects of glyphosate on microbes of agricultural soils are generally minor and transient, with other agricultural practices having much stronger effects.
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Affiliation(s)
- Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS, USA.
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10
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Duke SO, Pan Z, Bajsa-Hirschel J. Proving the Mode of Action of Phytotoxic Phytochemicals. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1756. [PMID: 33322386 PMCID: PMC7763512 DOI: 10.3390/plants9121756] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/22/2022]
Abstract
Knowledge of the mode of action of an allelochemical can be valuable for several reasons, such as proving and elucidating the role of the compound in nature and evaluating its potential utility as a pesticide. However, discovery of the molecular target site of a natural phytotoxin can be challenging. Because of this, we know little about the molecular targets of relatively few allelochemicals. It is much simpler to describe the secondary effects of these compounds, and, as a result, there is much information about these effects, which usually tell us little about the mode of action. This review describes the many approaches to molecular target site discovery, with an attempt to point out the pitfalls of each approach. Clues from molecular structure, phenotypic effects, physiological effects, omics studies, genetic approaches, and use of artificial intelligence are discussed. All these approaches can be confounded if the phytotoxin has more than one molecular target at similar concentrations or is a prophytotoxin, requiring structural alteration to create an active compound. Unequivocal determination of the molecular target site requires proof of activity on the function of the target protein and proof that a resistant form of the target protein confers resistance to the target organism.
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Affiliation(s)
- Stephen O. Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, MS 38655, USA
| | - Zhiqiang Pan
- Natural Products Utilization Research Unit, Agricultural Research Service, United States Department of Agriculture, Oxford, MS 38655, USA; (Z.P.); (J.B.-H.)
| | - Joanna Bajsa-Hirschel
- Natural Products Utilization Research Unit, Agricultural Research Service, United States Department of Agriculture, Oxford, MS 38655, USA; (Z.P.); (J.B.-H.)
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11
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Einhardt AM, Ferreira S, Oliveira LM, Ribeiro DM, Rodrigues FÁ. Glyphosate and nickel differently affect photosynthesis and ethylene in glyphosate-resistant soybean plants infected by Phakopsora pachyrhizi. PHYSIOLOGIA PLANTARUM 2020; 170:592-606. [PMID: 32918487 DOI: 10.1111/ppl.13195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/29/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Nickel (Ni) and glyphosate (Gl) are able to reduce the symptoms of Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, in soybean. However, their combined effects on the energy balance and ethylene metabolism of soybean plants infected with this fungus has not been elucidated. Therefore, the effects of Ni, Gl, and the combination of Ni + Gl on ASR development, photosynthetic capacity, sugar concentrations, and ethylene concentrations in plants of a Gl-resistant cultivar, uninfected or infected with P. pachyrhizi, were investigated. Inoculated plants supplied with Ni had the highest foliar Ni concentration in all the treatments. Gl had a negative effect on the foliar Ni concentration in Ni-sprayed plants. The ASR severity was reduced in plants sprayed with Ni and Gl. Carotenoid and chlorophyll concentrations were higher in inoculated Ni, Gl, and Ni + Gl plants than in control plants. Based on the chlorophyll a fluorescence parameters, the photosynthetic apparatus of the control inoculated plants was damaged, and the least amount of energy was directed to the photochemistry process in these plants. The reduced capacity of the photosynthetic mechanism to capture light and use the energy absorbed by photosystem II in inoculated plants was reflected in their reduced capacity to process CO2 , as indicated by the high internal CO2 concentrations and low rates of net carbon assimilation. The low sugar concentrations in inoculated plants from the control treatment were linked to their reduced photosynthetic capacity due to the high ASR severity. In uninfected plants, the ethylene concentration was not affected by Ni or Gl, while the ethylene concentration decreased in inoculated plants; this decrease was more pronounced in plants from the control treatment than in treated inoculated plants. In conclusion, this study sheds light on the role played by both Ni and Gl in ASR control from a physiological perspective. Soybean plants exposed to Ni and Gl were able to maintain high ethylene concentrations and photosynthetic capacity during the P. pachyrhizi infection process; as a result, these plants consumed less of their reserves than inoculated plants not treated with Ni or Gl.
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Affiliation(s)
- Andersom Milech Einhardt
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Laboratório da Interação Planta-Patógeno, Viçosa, 36570-900, Brazil
| | - Sandro Ferreira
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Laboratório da Interação Planta-Patógeno, Viçosa, 36570-900, Brazil
| | - Lillian Mathias Oliveira
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Laboratório da Interação Planta-Patógeno, Viçosa, 36570-900, Brazil
| | - Dimas Mendes Ribeiro
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, 36570-900, Brazil
| | - Fabrício Ávila Rodrigues
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Laboratório da Interação Planta-Patógeno, Viçosa, 36570-900, Brazil
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Finley JW, Duke SO. Agnes Rimando, a Pioneer in the Fate of Glyphosate and Its Primary Metabolite in Plants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:5623-5630. [PMID: 32330026 DOI: 10.1021/acs.jafc.0c00811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Glyphosate is the most used herbicide on the planet because of its excellent efficacy on almost all weed species and due to the large-scale adoption of transgenic, glyphosate-resistant (GR) crops. Agnes Rimando became an expert in glyphosate analysis almost 20 years ago to support research on GR crop safety and on mechanisms of evolved glyphosate resistance by weeds. Her work was the first to show that the amount of glyphosate and its primary metabolite aminomethylphosphonic acid (AMPA) that accumulates in GR soybean seed from plants treated with approved glyphosate doses can approach their legal limits. However, she later found that only trace amounts of these compounds accumulate in the seed of GR maize treated with recommended glyphosate doses. She showed that GR canola, the only transgenic crop with a transgene encoding an enzyme for degradation of glyphosate, metabolizes glyphosate to AMPA very rapidly. Her work was instrumental in providing support for the view that "yellow flash" symptoms sometimes observed in field-grown GR soybeans are due to accumulation of enough AMPA to cause mild phytotoxicity. She did the chemical analyses in the only paper to survey the capacity of an array of plant species to metabolize glyphosate to AMPA. She found a wide range in this capacity, with grasses with little or no metabolism of glyphosate to AMPA and with legumes readily metabolizing glyphosate. Lastly, she found no evidence of enhanced degradation of glyphosate to be a mechanism of evolved resistance to glyphosate by two weed species but that it might be involved in natural tolerance to glyphosate of some weeds.
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Affiliation(s)
- John W Finley
- Department of Nutrition and Food Sciences Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Stephen O Duke
- National Center for Natural Products Research School of Pharmacy University of Mississippi University, Mississippi 38677-8048, United States
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13
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Smedbol É, Lucotte M, Maccario S, Gomes MP, Paquet S, Moingt M, Mercier LLC, Sobarzo MRP, Blouin MA. Glyphosate and Aminomethylphosphonic Acid Content in Glyphosate-Resistant Soybean Leaves, Stems, and Roots and Associated Phytotoxicity Following a Single Glyphosate-Based Herbicide Application. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:6133-6142. [PMID: 31067046 DOI: 10.1021/acs.jafc.9b00949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Glyphosate-based herbicide (GBH) applications were reported to induce physiological damages to glyphosate-resistant (GR) soybean, which were mainly attributed to aminomethylphosphonic acid (AMPA). In order to study glyphosate and AMPA dynamics in plants and associated phytotoxic effects, a greenhouse experiment was set where GR soybeans were exposed to GBH (0.7 to 4.5 kg glyphosate ha-1) and sampled over time (2, 7, 14, and 28 days after treatment (DAT)). Hydrogen peroxide content increased 2 DAT, while a decrease was observed for the effective quantum yield (2, 7, 14 DAT), stomatal conductance (2 DAT), and biomass (14 DAT). Glyphosate content was higher in leaves, followed by stems, and then roots. AMPA content tended to increase with time, especially in roots, and the amount of AMPA in roots was negatively correlated to mostly all phytotoxicity indicators. This finding is important since AMPA residues are measured in agricultural soils several months after GBH applications, which could impact productivity in GR crops.
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Affiliation(s)
- Élise Smedbol
- Université du Québec à Montréal , GEOTOP & Institut des Sciences de l'Environnement , 201 Avenue du Président-Kennedy , H2X 3Y7 Montréal , Québec , Canada
| | - Marc Lucotte
- Université du Québec à Montréal , GEOTOP & Institut des Sciences de l'Environnement , 201 Avenue du Président-Kennedy , H2X 3Y7 Montréal , Québec , Canada
| | - Sophie Maccario
- Université du Québec à Montréal , GEOTOP & Institut des Sciences de l'Environnement , 201 Avenue du Président-Kennedy , H2X 3Y7 Montréal , Québec , Canada
| | - Marcelo Pedrosa Gomes
- Universidade Federal do Paraná , Departamento de Botânica, Setor de Ciências Biológicas , 80050-540 Curitiba , Paraná , Brazil
| | - Serge Paquet
- Université du Québec à Montréal , Département des Sciences Biologiques , 141 Avenue du Président-Kennedy , H2X 1Y4 Montréal , Québec , Canada
| | - Matthieu Moingt
- Université du Québec à Montréal , GEOTOP & Institut des Sciences de l'Environnement , 201 Avenue du Président-Kennedy , H2X 3Y7 Montréal , Québec , Canada
| | - Lila Lucero Celis Mercier
- Université du Québec à Montréal , Département des Sciences Biologiques , 141 Avenue du Président-Kennedy , H2X 1Y4 Montréal , Québec , Canada
| | - Millaray Rayen Perez Sobarzo
- Université du Québec à Montréal , Département de Chimie , 2101 rue Jeanne-Mance , H2X 2J6 Montréal , Québec , Canada
| | - Marc-André Blouin
- Université du Québec à Montréal , Département de Chimie , 2101 rue Jeanne-Mance , H2X 2J6 Montréal , Québec , Canada
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Cardoso-Gustavson P, Dias MG, Costa FOB, de Moura Leite Camargos G, da Cruz Centeno D. Imaging of glyphosate uptake and identification of early microscopic markers in leaves of C3 and C4 glyphosate-resistant and -susceptible species. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 163:502-513. [PMID: 30075454 DOI: 10.1016/j.ecoenv.2018.07.096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/12/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Details of glyphosate uptake are not fully elucidated, and although this herbicide promotes important alterations in the plant phenotype few hours after its application (early responses), a detailed description of the presumable changes in plant anatomy is still poorly assessed by now. Due to glyphosate effects over leaf permeability, the use of an inert fluorescent tracer may allow the observation of the uptake event in situ. In addition, microscopic markers might put a light on the recognition of glyphosate-resistant (GR) and -susceptible (GS) species or varieties, which may vary in C3 and C4 species due to their putative distinct leaf anatomy. Here we aimed (i) to provide a new technique to track the route of glyphosate formulation towards leaf tissues using a fluorescent tracer, and (ii) to describe the early specific microscopic alterations in GR and GS -C3 or -C4 caused by the glyphosate formulation. Roundup Transorb® was applied in seedlings cultivated in a greenhouse and response alterations in leaf anatomy were described. Lucifer Yellow CH (LYCH) was applied over the same region where glyphosate formulation was previously applied to track the alterations in leaf permeability caused by this herbicide. LYCH successfully tracked the glyphosate formulation uptake, reaching the vascular bundles of GS species, and becoming retained in leaf tissues of GR species. All species exhibited a decrease in chlorophyll content at the site of glyphosate application regardless of their photosynthetic metabolism or susceptibility. GS species showed alterations in chloroplast morphology and activity of non-enzymatic antioxidants (carotenoids and flavonoids), in addition to symptoms indicating a process of accelerated cell senescence. A specific type of cell necrosis (hypersensitive response) was observed in GR-C4 species as a way to prevent the translocation of this herbicide, while GR-C3 species accumulated phenolic compounds inside the vacuole, probably sequestrating and inactivating the glyphosate action. This study provides a reliable tool to track glyphosate formulation uptake in situ and is the first attempt to the identification of early specific microscopic markers caused by glyphosate formulation.
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Affiliation(s)
- Poliana Cardoso-Gustavson
- Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, 09606-070 São Bernardo do Campo, Brazil; Oxiteno S.A., Research and Development, Agrochemicals, 09380-440 Mauá, Brazil.
| | - Marcia Gonçalves Dias
- Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, 09606-070 São Bernardo do Campo, Brazil
| | - Fernanda Oliveira Barreto Costa
- Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, 09606-070 São Bernardo do Campo, Brazil; Oxiteno S.A., Research and Development, Agrochemicals, 09380-440 Mauá, Brazil
| | | | - Danilo da Cruz Centeno
- Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, 09606-070 São Bernardo do Campo, Brazil
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Reddy KN, Cizdziel JV, Williams MM, Maul JE, Rimando AM, Duke SO. Glyphosate Resistance Technology Has Minimal or No Effect on Maize Mineral Content and Yield. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:10139-10146. [PMID: 30203974 DOI: 10.1021/acs.jafc.8b01655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controversy continues to exist regarding whether the transgene for glyphosate resistance (GR) and/or glyphosate applied to GR crops adversely affect plant mineral content. Field studies were conducted in 2013 and 2014 in Stoneville, MS and Urbana, IL to examine this issue in maize. At each location, the experiment was conducted in fields with no history of glyphosate application and fields with several years of glyphosate use preceding the study. Neither glyphosate nor the GR transgene affected yield or mineral content of leaves or seed, except for occasional (<5%) significant effects that were inconsistent across minerals, treatments, and environments. Glyphosate and AMPA (aminomethylphosphonic acid), a main degradation product of glyphosate, were found in leaves from treated plants, but little or no glyphosate and no AMPA was found in maize seeds. These results show that the GR transgene and glyphosate application, whether used for a single year or several years, have no deleterious effect on mineral nutrition or yield of GR maize.
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Affiliation(s)
- Krishna N Reddy
- Crop Production Systems Research Unit, USDA-ARS , P.O. Box 350, Stoneville , Mississippi 38776 , United States
| | - James V Cizdziel
- Department of Chemistry and Biochemistry , University of Mississippi , 222 Coulter Hall , University , Mississippi 38677 , United States
| | - Martin M Williams
- Global Change and Photosynthesis Research unit , USDA-ARS, 1102 S. Goodwin Avenue , Urbana , Illinois 61801 , United States
| | - Jude E Maul
- Sustainable Agricultural Systems Laboratory, USDA-ARS , 10300 Baltimore Avenue , Beltsville , Maryland 20705 , United States
| | - Agnes M Rimando
- Natural Products Utilization Research Unit, USDA-ARS , P.O. Box 1848, University , Mississippi 38677 , United States
| | - Stephen O Duke
- Natural Products Utilization Research Unit, USDA-ARS , P.O. Box 1848, University , Mississippi 38677 , United States
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16
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Heap I, Duke SO. Overview of glyphosate-resistant weeds worldwide. PEST MANAGEMENT SCIENCE 2018; 74:1040-1049. [PMID: 29024306 DOI: 10.1002/ps.4760] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/05/2017] [Accepted: 10/05/2017] [Indexed: 05/06/2023]
Abstract
Glyphosate is the most widely used and successful herbicide discovered to date, but its utility is now threatened by the occurrence of several glyphosate-resistant weed species. Glyphosate resistance first appeared in Lolium rigidum in an apple orchard in Australia in 1996, ironically the year that the first glyphosate-resistant crop (soybean) was introduced in the USA. Thirty-eight weed species have now evolved resistance to glyphosate, distributed across 37 countries and in 34 different crops and six non-crop situations. Although glyphosate-resistant weeds have been identified in orchards, vineyards, plantations, cereals, fallow and non-crop situations, it is the glyphosate-resistant weeds in glyphosate-resistant crop systems that dominate the area infested and growing economic impact. Glyphosate-resistant weeds present the greatest threat to sustained weed control in major agronomic crops because this herbicide is used to control weeds with resistance to herbicides with other sites of action, and no new herbicide sites of action have been introduced for over 30 years. Industry has responded by developing herbicide resistance traits in major crops that allow existing herbicides to be used in a new way. However, over reliance on these traits will result in multiple-resistance in weeds. Weed control in major crops is at a precarious point, where we must maintain the utility of the herbicides we have until we can transition to new weed management technologies. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Ian Heap
- International Survey of Herbicide-Resistant Weeds, Corvallis, OR, USA
| | - Stephen O Duke
- USDA, ARS, Natural Products Utilization Research Unit, National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, MS, USA
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17
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Duke SO, Rimando AM, Reddy KN, Cizdziel JV, Bellaloui N, Shaw DR, Williams MM, Maul JE. Lack of transgene and glyphosate effects on yield, and mineral and amino acid content of glyphosate-resistant soybean. PEST MANAGEMENT SCIENCE 2018; 74:1166-1173. [PMID: 28547884 DOI: 10.1002/ps.4625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 05/12/2017] [Accepted: 05/23/2017] [Indexed: 05/09/2023]
Abstract
BACKGROUND There has been controversy as to whether the glyphosate resistance gene and/or glyphosate applied to glyphosate-resistant (GR) soybean affect the content of cationic minerals (especially Mg, Mn and Fe), yield and amino acid content of GR soybean. A two-year field study (2013 and 2014) examined these questions at sites in Mississippi, USA. RESULTS There were no effects of glyphosate, the GR transgene or field crop history (for a field with both no history of glyphosate use versus one with a long history of glyphosate use) on grain yield. Furthermore, these factors had no consistent effects on measured mineral (Al, As, Ba, Cd, Ca, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Ni, Pb, Rb, Se, Sr, Tl, U, V, Zn) content of leaves or harvested seed. Effects on minerals were small and inconsistent between years, treatments and mineral, and appeared to be random false positives. No notable effects on free or protein amino acids of the seed were measured, although glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), were found in the seed in concentrations consistent with previous studies. CONCLUSIONS Neither glyphosate nor the GR transgene affect the content of the minerals measured in leaves and seed, harvested seed amino acid composition, or yield of GR soybean. Furthermore, soils with a legacy of GR crops have no effects on these parameters in soybean. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Stephen O Duke
- U.S. Department of Agriculture-Agricultural Research Service, Natural Products Utilization Research Unit, University, MS, USA
| | - Agnes M Rimando
- U.S. Department of Agriculture-Agricultural Research Service, Natural Products Utilization Research Unit, University, MS, USA
| | - Krishna N Reddy
- USDA-ARS, Crop Production Systems Research Unit, Stoneville, MS, USA
| | - James V Cizdziel
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, USA
| | | | - David R Shaw
- Research and Economic Development, Mississippi State University, Mississippi State, MS, USA
| | - Martin M Williams
- USDA-ARS, Global Change and Photosynthesis Research Unit, Urbana, IL, USA
| | - Jude E Maul
- USDA-ARS, Sustainable Agricultural Systems Laboratory, Beltsville, MD, USA
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18
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Pandolfo CE, Presotto A, Carbonell FT, Ureta S, Poverene M, Cantamutto M. Transgenic glyphosate-resistant oilseed rape (Brassica napus) as an invasive weed in Argentina: detection, characterization, and control alternatives. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:24081-24091. [PMID: 27638808 DOI: 10.1007/s11356-016-7670-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/09/2016] [Indexed: 06/06/2023]
Abstract
The presence of glyphosate-resistant oilseed rape populations in Argentina was detected and characterized. The resistant plants were found as weeds in RR soybeans and other fields. The immunological and molecular analysis showed that the accessions presented the GT73 transgenic event. The origin of this event was uncertain, as the cultivation of transgenic oilseed rape cultivars is prohibited in Argentina. This finding might suggest that glyphosate resistance could come from unauthorized transgenic oilseed rape crops cultivated in the country or as seed contaminants in imported oilseed rape cultivars or other seed imports. Experimentation showed that there are alternative herbicides for controlling resistant Brassica napus populations in various situations and crops. AHAS-inhibiting herbicides (imazethapyr, chlorimuron and diclosulam), glufosinate, 2,4-D, fluroxypyr and saflufenacil proved to be very effective in controlling these plants. Herbicides evaluated in this research were employed by farmers in one of the fields invaded with this biotype and monitoring of this field showed no evidence of its presence in the following years.
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Affiliation(s)
- Claudio E Pandolfo
- Departamento de Agronomía, Universidad Nacional del Sur, San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina.
| | - Alejandro Presotto
- Departamento de Agronomía, Universidad Nacional del Sur, San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - Francisco Torres Carbonell
- Departamento de Agronomía, Universidad Nacional del Sur, San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
| | - Soledad Ureta
- Departamento de Agronomía, Universidad Nacional del Sur, San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - Mónica Poverene
- Departamento de Agronomía, Universidad Nacional del Sur, San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - Miguel Cantamutto
- Departamento de Agronomía, Universidad Nacional del Sur, San Andrés 800, 8000, Bahía Blanca, Buenos Aires, Argentina
- Estación Experimental Agropecuaria Hilario Ascasubi, Instituto Nacional de Tecnología Agropecuaria (INTA), Ruta 3 Km 794, 8142, Hilario Ascasubi, Villarino, Argentina
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19
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Mamy L, Barriuso E, Gabrielle B. Glyphosate fate in soils when arriving in plant residues. CHEMOSPHERE 2016; 154:425-433. [PMID: 27077537 DOI: 10.1016/j.chemosphere.2016.03.104] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 03/09/2016] [Accepted: 03/19/2016] [Indexed: 06/05/2023]
Abstract
A significant fraction of pesticides sprayed on crops may be returned to soils via plant residues, but its fate has been little documented. The objective of this work was to study the fate of glyphosate associated to plants residues. Oilseed rape was used as model plant using two lines: a glyphosate-tolerant (GT) line and a non-GT one, considered as a crucifer weed. The effects of different fragmentation degrees and placements in soil of plant residues were tested. A control was set up by spraying glyphosate directly on the soil. The mineralization of glyphosate in soil was slower when incorporated into plant residues, and the amounts of extractable and non-extractable glyphosate residues increased. Glyphosate availability for mineralization increased when the size of plant residues decreased, and as the distribution of plant residues in soil was more homogeneous. After 80 days of soil incubation, extractable (14)C-residues mostly involved one metabolite of glyphosate (AMPA) but up to 2.6% of initial (14)C was still extracted from undecayed leaves as glyphosate. Thus, the trapping of herbicides in plant materials provided a protection against degradation, and crops residues returns may increase the persistence of glyphosate in soils. This pattern appeared more pronounced for GT crops, which accumulated more non-degraded glyphosate in their tissues.
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Affiliation(s)
- Laure Mamy
- UMR ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France.
| | - Enrique Barriuso
- UMR ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France.
| | - Benoît Gabrielle
- UMR ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France.
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Corrêa EA, Dayan FE, Owens DK, Rimando AM, Duke SO. Glyphosate-Resistant and Conventional Canola (Brassica napus L.) Responses to Glyphosate and Aminomethylphosphonic Acid (AMPA) Treatment. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:3508-13. [PMID: 27092715 DOI: 10.1021/acs.jafc.6b00446] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Glyphosate-resistant (GR) canola contains two transgenes that impart resistance to the herbicide glyphosate: (1) the microbial glyphosate oxidase gene (gox) encoding the glyphosate oxidase enzyme (GOX) that metabolizes glyphosate to aminomethylphosphonic acid (AMPA) and (2) cp4 that encodes a GR form of the glyphosate target enzyme 5-enolpyruvylshikimic acid-3-phosphate synthase. The objectives of this research were to determine the phytotoxicity of AMPA to canola, the relative metabolism of glyphosate to AMPA in GR and conventional non-GR (NGR) canola, and AMPA pool sizes in glyphosate-treated GR canola. AMPA applied at 1.0 kg ha(-1) was not phytotoxic to GR or NGR. At this AMPA application rate, NGR canola accumulated a higher concentration of AMPA in its tissues than GR canola. At rates of 1 and 3.33 kg ae ha(-1) of glyphosate, GR canola growth was stimulated. This stimulatory effect is similar to that of much lower doses of glyphosate on NGR canola. Both shikimate and AMPA accumulated in tissues of these glyphosate-treated plants. In a separate experiment in which young GR and NGR canola plants were treated with non-phytotoxic levels of [(14)C]-glyphosate, very little glyphosate was metabolized in NGR plants, whereas most of the glyphosate was metabolized to AMPA in GR plants at 7 days after application. Untreated leaves of GR plants accumulated only metabolites (mostly AMPA) of glyphosate, indicating that GOX activity is very high in the youngest leaves. These data indicate that more glyphosate is transformed to AMPA rapidly in GR canola and that the accumulated AMPA is not toxic to the canola plant.
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Affiliation(s)
- Elza Alves Corrêa
- UNESP, Universidade Estadual Paulista "Júlio de Mesquita Filho", Campus de Registro/SP, Rua Nelson Brihi Badur 430, 11900-000 Registro, SP, Brazil
| | - Franck E Dayan
- Natural Products Utilization Research Unit, Agricultural Research Service, U.S. Department of Agriculture , P.O. Box 1848, University, Mississippi 38677, United States
| | - Daniel K Owens
- Natural Products Utilization Research Unit, Agricultural Research Service, U.S. Department of Agriculture , P.O. Box 1848, University, Mississippi 38677, United States
| | - Agnes M Rimando
- Natural Products Utilization Research Unit, Agricultural Research Service, U.S. Department of Agriculture , P.O. Box 1848, University, Mississippi 38677, United States
| | - Stephen O Duke
- Natural Products Utilization Research Unit, Agricultural Research Service, U.S. Department of Agriculture , P.O. Box 1848, University, Mississippi 38677, United States
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21
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Tani E, Chachalis D, Travlos IS, Bilalis D. Environmental Conditions Influence Induction of Key ABC-Transporter Genes Affecting Glyphosate Resistance Mechanism in Conyza canadensis. Int J Mol Sci 2016; 17:E342. [PMID: 27104532 PMCID: PMC4848879 DOI: 10.3390/ijms17040342] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 10/11/2015] [Accepted: 02/29/2016] [Indexed: 11/17/2022] Open
Abstract
Conyza canadensis has been reported to be the most frequent weed species that evolved resistance to glyphosate in various parts of the world. The objective of the present study was to investigate the effect of environmental conditions (temperature and light) on the expression levels of the EPSPS gene and two major ABC-transporter genes (M10 and M11) on glyphosate susceptible (GS) and glyphosate resistant (GR) horseweed populations, collected from several regions across Greece. Real-time PCR was conducted to determine the expression level of the aforementioned genes when glyphosate was applied at normal (1×; 533 g·a.e.·ha(-1)) and high rates (4×, 8×), measured at an early one day after treatment (DAT) and a later stage (four DAT) of expression. Plants were exposed to light or dark conditions, at three temperature regimes (8, 25, 35 °C). GR plants were made sensitive when exposed to 8 °C with light; those sensitized plants behaved biochemically (shikimate accumulation) and molecularly (expression of EPSPS and ABC-genes) like the GS plants. Results from the current study show the direct link between the environmental conditions and the induction level of the above key genes that likely affect the efficiency of the proposed mechanism of glyphosate resistance.
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Affiliation(s)
- Eleni Tani
- Laboratory of Plant Breeding, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
| | - Demosthenis Chachalis
- Laboratory of Weed Science, Benaki Phytopathological Institute, S. Delta 8, 14561 Athens, Greece.
| | - Ilias S Travlos
- Laboratory of Agronomy, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
| | - Dimitrios Bilalis
- Laboratory of Agronomy, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
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22
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The role of derivatization techniques in the analysis of glyphosate and aminomethyl-phosphonic acid by chromatography. Microchem J 2015. [DOI: 10.1016/j.microc.2015.02.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Nicolia A, Ferradini N, Molla G, Biagetti E, Pollegioni L, Veronesi F, Rosellini D. Expression of an evolved engineered variant of a bacterial glycine oxidase leads to glyphosate resistance in alfalfa. J Biotechnol 2014; 184:201-8. [PMID: 24905148 DOI: 10.1016/j.jbiotec.2014.05.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/14/2014] [Accepted: 05/16/2014] [Indexed: 11/27/2022]
Abstract
The main strategy for resistance to the herbicide glyphosate in plants is the overexpression of an herbicide insensitive, bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). A glyphosate resistance strategy based on the ability to degrade the herbicide can be useful to reduce glyphosate phytotoxicity to the crops. Here we present the characterization of glyphosate resistance in transgenic alfalfa (Medicago sativa L.) expressing a plant-optimized variant of glycine oxidase (GO) from Bacillus subtilis, evolved in vitro by a protein engineering approach to efficiently degrade glyphosate. Two constructs were used, one with (GO(TP+)) and one without (GO(TP-)) the pea rbcS plastid transit peptide. Molecular and biochemical analyses confirmed the stable integration of the transgene and the correct localization of the plastid-imported GO protein. Transgenic alfalfa plants were tested for glyphosate resistance both in vitro and in vivo. Two GO(TP+) lines showed moderate resistance to the herbicide in both conditions. Optimization of expression of this GO variant may allow to attain sufficient field resistance to glyphosate herbicides, thus providing a resistance strategy based on herbicide degradation.
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Affiliation(s)
- A Nicolia
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy.
| | - N Ferradini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
| | - G Molla
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J.H. Dunant 3, 21100 Varese, Italy; Centro Interuniversitario di Ricerca in Biotecnologie Proteiche The Protein Factory, Politecnico di Milano, ICRM CNR Milano and Università degli studi dell'Insubria, via Mancinelli 7, 20131 Milano, Italy
| | - E Biagetti
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
| | - L Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J.H. Dunant 3, 21100 Varese, Italy; Centro Interuniversitario di Ricerca in Biotecnologie Proteiche The Protein Factory, Politecnico di Milano, ICRM CNR Milano and Università degli studi dell'Insubria, via Mancinelli 7, 20131 Milano, Italy
| | - F Veronesi
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
| | - D Rosellini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
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Huang ZF, Zhang CX, Huang HJ, Wei SH, Liu Y, Cui HL, Chen JC, Yang L, Chen JY. Molecular cloning and characterization of 5-enolpyruvylshikimate-3-phosphate synthase gene from Convolvulus arvensis L. Mol Biol Rep 2014; 41:2077-84. [PMID: 24413996 DOI: 10.1007/s11033-014-3056-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 01/04/2014] [Indexed: 11/27/2022]
Abstract
5-Enolpyruvylshikimate-3-phosphate synthase (EPSPS), the target enzyme for glyphosate inhibition, catalyzes an essential step in the shikimate pathway for aromatic amino acid biosynthesis. The full-length cDNA of 1,751 nucleotides (CaEPSPS, Genbank accession number: EU698030) from Convolvulus arvensis was cloned and characterized. The CaEPSPS encodes a polypeptide of 520 amino acids with a calculated molecular weight of 55.5 kDa and an isoelectric point of 7.05. The results of homology analysis revealed that CaEPSPS showed highly homologous with EPSPS proteins from other plant species. Tissue expression pattern analysis indicated that CaEPSPS was constitutively expressed in stems, leaves and roots, with lower expression in roots. CaEPSPS expression level could increase significantly with glyphosate treatment, and reached its maximum at 24 h after glyphosate application. We fused CaEPSPS to the CaMV 35S promoter and introduced the chimeric gene into Arabidopsis. The resultant expression of CaEPSPS in transgenic Arabidopsis plants exhibited enhanced tolerance to glyphosate in comparison with control.
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Affiliation(s)
- Zhao-Feng Huang
- Institute of Plant Protection, Key Laboratory of Weed and Rodent Biology and Management, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
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Zhan T, Zhang K, Chen Y, Lin Y, Wu G, Zhang L, Yao P, Shao Z, Liu Z. Improving glyphosate oxidation activity of glycine oxidase from Bacillus cereus by directed evolution. PLoS One 2013; 8:e79175. [PMID: 24223901 PMCID: PMC3818420 DOI: 10.1371/journal.pone.0079175] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/20/2013] [Indexed: 11/18/2022] Open
Abstract
Glyphosate, a broad spectrum herbicide widely used in agriculture all over the world, inhibits 5-enolpyruvylshikimate-3-phosphate synthase in the shikimate pathway, and glycine oxidase (GO) has been reported to be able to catalyze the oxidative deamination of various amines and cleave the C-N bond in glyphosate. Here, in an effort to improve the catalytic activity of the glycine oxidase that was cloned from a glyphosate-degrading marine strain of Bacillus cereus (BceGO), we used a bacteriophage T7 lysis-based method for high-throughput screening of oxidase activity and engineered the gene encoding BceGO by directed evolution. Six mutants exhibiting enhanced activity toward glyphosate were screened from two rounds of error-prone PCR combined with site directed mutagenesis, and the beneficial mutations of the six evolved variants were recombined by DNA shuffling. Four recombinants were generated and, when compared with the wild-type BceGO, the most active mutant B3S1 showed the highest activity, exhibiting a 160-fold increase in substrate affinity, a 326-fold enhancement in catalytic efficiency against glyphosate, with little difference between their pH and temperature stabilities. The role of these mutations was explored through structure modeling and molecular docking, revealing that the Arg(51) mutation is near the active site and could be an important residue contributing to the stabilization of glyphosate binding, while the role of the remaining mutations is unclear. These results provide insight into the application of directed evolution in optimizing glycine oxidase function and have laid a foundation for the development of glyphosate-tolerant crops.
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Affiliation(s)
- Tao Zhan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Kai Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Yangyan Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Yongjun Lin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Gaobing Wu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Lili Zhang
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Production and Construction Corps, College of Life Science, Tarim University, Alar, Xinjiang, P. R. China
| | - Pei Yao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Zongze Shao
- Key Laboratory of Marine Biogenetic Resources, the Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian, P. R. China
| | - Ziduo Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
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Serra AA, Nuttens A, Larvor V, Renault D, Couée I, Sulmon C, Gouesbet G. Low environmentally relevant levels of bioactive xenobiotics and associated degradation products cause cryptic perturbations of metabolism and molecular stress responses in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2753-66. [PMID: 23645866 DOI: 10.1093/jxb/ert119] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Anthropic changes and chemical pollution confront wild plant communities with xenobiotic combinations of bioactive molecules, degradation products, and adjuvants that constitute chemical challenges potentially affecting plant growth and fitness. Such complex challenges involving residual contamination and mixtures of pollutants are difficult to assess. The model plant Arabidopsis thaliana was confronted by combinations consisting of the herbicide glyphosate, the fungicide tebuconazole, the glyphosate degradation product aminomethylphosphonic acid (AMPA), and the atrazine degradation product hydroxyatrazine, which had been detected and quantified in soils of field margins in an agriculturally intensive region. Integrative analysis of physiological, metabolic, and gene expression responses was carried out in dose-response experiments and in comparative experiments of varying pesticide combinations. Field margin contamination levels had significant effects on plant growth and metabolism despite low levels of individual components and the presence of pesticide degradation products. Biochemical and molecular analysis demonstrated that these less toxic degradation products, AMPA and hydroxyatrazine, by themselves elicited significant plant responses, thus indicating underlying mechanisms of perception and transduction into metabolic and gene expression changes. These mechanisms may explain observed interactions, whether positive or negative, between the effects of pesticide products (AMPA and hydroxyatrazine) and the effects of bioactive xenobiotics (glyphosate and tebuconazole). Finally, the metabolic and molecular perturbations induced by low levels of xenobiotics and associated degradation products were shown to affect processes (carbon balance, hormone balance, antioxidant defence, and detoxification) that are likely to determine environmental stress sensitivity.
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Affiliation(s)
- Anne-Antonella Serra
- Université de Rennes 1, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, bâtiment 14A. 263 avenue du Général Leclerc, F-35042 Rennes Cedex, France
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González-Torralva F, Rojano-Delgado AM, Luque de Castro MD, Mülleder N, De Prado R. Two non-target mechanisms are involved in glyphosate-resistant horseweed (Conyza canadensis L. Cronq.) biotypes. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:1673-9. [PMID: 22841626 DOI: 10.1016/j.jplph.2012.06.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/28/2012] [Accepted: 06/22/2012] [Indexed: 06/01/2023]
Abstract
The physiological and biochemical bases for glyphosate resistance and susceptibility in horseweed (Conyza canadensis L. Cronq.) populations collected from Córdoba, Huelva, Málaga, Jaén and Seville in southern Spain were investigated. Screening 25 populations treated with glyphosate (238gacidequivalentha(-1)) at the rosette stage (BBCH 14-15) revealed reductions in fresh weight (fw) of 9-99%. The resistant biotype (R C004) was 6.1 times more resistant than the susceptible biotype (S). Shikimate accumulation in both biotypes increased until 72h after treatment (HAT), and then continued to increase (to 61.2%) in the S biotype, but decreased by 40% in the R (C004) biotype. Differential glyphosate spray retention and foliar uptake of applied (14)C-glyphosate between the R (C004) and S biotype had no effect on resistance to this herbicide. Quantitative and qualitative tests showed greater (14)C-glyphosate mobility in the S biotype than in the R (C004) biotype. Glyphosate was metabolized faster in the R (C004) biotype than in the S biotype. The herbicide disappeared completely from the R (C004) biotype by conversion into glyoxylate, sarcosine and aminomethylphosphonic acid within 96 HAT. On the other hand, 41.43nmolg(-1)fw of all glyphosate applied remained in the S biotype and glyoxylate was its only non-toxic metabolite. These results suggest that glyphosate resistance in horseweed is due to two different non-target mechanisms, namely: (a) impaired glyphosate translocation and (b) glyphosate metabolism to other compounds.
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Duke SO, Lydon J, Koskinen WC, Moorman TB, Chaney RL, Hammerschmidt R. Glyphosate effects on plant mineral nutrition, crop rhizosphere microbiota, and plant disease in glyphosate-resistant crops. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:10375-97. [PMID: 23013354 PMCID: PMC3479986 DOI: 10.1021/jf302436u] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/24/2012] [Accepted: 09/26/2012] [Indexed: 05/09/2023]
Abstract
Claims have been made recently that glyphosate-resistant (GR) crops sometimes have mineral deficiencies and increased plant disease. This review evaluates the literature that is germane to these claims. Our conclusions are: (1) although there is conflicting literature on the effects of glyphosate on mineral nutrition on GR crops, most of the literature indicates that mineral nutrition in GR crops is not affected by either the GR trait or by application of glyphosate; (2) most of the available data support the view that neither the GR transgenes nor glyphosate use in GR crops increases crop disease; and (3) yield data on GR crops do not support the hypotheses that there are substantive mineral nutrition or disease problems that are specific to GR crops.
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Affiliation(s)
- Stephen O Duke
- USDA, ARS Natural Products Utilization Research Unit, P.O. Box 8048, University, Mississippi 38677, USA.
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Duke SO, Reddy KN, Bu K, Cizdziel JV. Effects of glyphosate on the mineral content of glyphosate-resistant soybeans (Glycine max). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:6764-71. [PMID: 22708739 DOI: 10.1021/jf3014603] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
There are conflicting claims as to whether treatment with glyphosate adversely affects mineral nutrition of glyphosate-resistant (GR) crops. Those who have made claims of adverse effects have argued links between reduced Mn and diseases in these crops. This article describes experiments designed to determine the effects of a recommended rate (0.86 kg ha(-1)) of glyphosate applied once or twice on the mineral content of young and mature leaves, as well as in seeds produced by GR soybeans (Glycine max) in both the greenhouse and field using inductively coupled plasma mass spectrometry (ICP-MS). In the greenhouse, there were no effects of either one application (at 3 weeks after planting, WAP) or two applications (at 3 and 6 WAP) of glyphosate on Ca, Mg, Mn, Zn, Fe, Cu, Sr, Ba, Al, Cd, Cr, Co, or Ni content of young or old leaves sampled at 6, 9, and 12 WAP and in harvested seed. Se concentrations were too low for accurate detection in leaves, but there was also no effect of glyphosate applications on Se in the seeds. In the field study, there were no effects of two applications (at 3 and 6 WAP) of glyphosate on Ca, Mg, Mn, Zn, Fe, Cu, Sr, Ba, Al, Cd, Cr, Co, or Ni content of young or old leaves at either 9 or 12 WAP. There was also no effect on Se in the seeds. There was no difference in yield between control and glyphosate-treated GR soybeans in the field. The results indicate that glyphosate does not influence mineral nutrition of GR soybean at recommended rates for weed management in the field. Furthermore, the field studies confirm the results of greenhouse studies.
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Affiliation(s)
- Stephen O Duke
- USDA , ARS, Natural Product Utilization Research Unit, University, Mississippi 38677, United States
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Kleter GA, Unsworth JB, Harris CA. The impact of altered herbicide residues in transgenic herbicide-resistant crops on standard setting for herbicide residues. PEST MANAGEMENT SCIENCE 2011; 67:1193-210. [PMID: 21898904 DOI: 10.1002/ps.2128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Accepted: 01/04/2011] [Indexed: 05/22/2023]
Abstract
The global area covered with transgenic (genetically modified) crops has rapidly increased since their introduction in the mid-1990s. Most of these crops have been rendered herbicide resistant, for which it can be envisaged that the modification has an impact on the profile and level of herbicide residues within these crops. In this article, the four main categories of herbicide resistance, including resistance to acetolactate-synthase inhibitors, bromoxynil, glufosinate and glyphosate, are reviewed. The topics considered are the molecular mechanism underlying the herbicide resistance, the nature and levels of the residues formed and their impact on the residue definition and maximum residue limits (MRLs) defined by the Codex Alimentarius Commission and national authorities. No general conclusions can be drawn concerning the nature and level of residues, which has to be done on a case-by-case basis. International residue definitions and MRLs are still lacking for some herbicide-crop combinations, and harmonisation is therefore recommended.
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Affiliation(s)
- Gijs A Kleter
- RIKILT-Institute of Food Safety, Wageningen University and Research Centre, Wageningen, Holland.
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Duke SO. Glyphosate degradation in glyphosate-resistant and -susceptible crops and weeds. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:5835-41. [PMID: 20919737 DOI: 10.1021/jf102704x] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
High levels of aminomethylphosphonic acid (AMPA), the main glyphosate metabolite, have been found in glyphosate-treated, glyphosate-resistant (GR) soybean, apparently due to plant glyphosate oxidoreductase (GOX)-like activity. AMPA is mildly phytotoxic, and under some conditions the AMPA accumulating in GR soybean correlates with glyphosate-caused phytotoxicity. A bacterial GOX is used in GR canola, and an altered bacterial glyphosate N-acetyltransferase is planned for a new generation of GR crops. In some weed species, glyphosate degradation could contribute to natural resistance. Neither an isolated plant GOX enzyme nor a gene for it has yet been reported in plants. Gene mutation or amplification of plant genes for GOX-like enzyme activity or horizontal transfer of microbial genes from glyphosate-degrading enzymes could produce GR weeds. Yet, there is no evidence that metabolic degradation plays a significant role in evolved resistance to glyphosate. This is unexpected, considering the extreme selection pressure for evolution of glyphosate resistance in weeds and the difficulty in plants of evolving glyphosate resistance via other mechanisms.
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Affiliation(s)
- Stephen O Duke
- NPURU, ARS, U.S. Department of Agriculture, P.O. Box 8048, University, Mississippi 38677, USA
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Zelaya IA, Anderson JAH, Owen MDK, Landes RD. Evaluation of spectrophotometric and HPLC methods for shikimic acid determination in plants: models in glyphosate-resistant and -susceptible crops. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:2202-12. [PMID: 21338087 DOI: 10.1021/jf1043426] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Endogenous shikimic acid determinations are routinely used to assess the efficacy of glyphosate in plants. Numerous analytical methods exist in the public domain for the detection of shikimic acid, yet the most commonly cited comprise spectrophotometric and high-pressure liquid chromatography (HPLC) methods. This paper compares an HPLC and two spectrophotometric methods (Spec 1 and Spec 2) and assesses the effectiveness in the detection of shikimic acid in the tissues of glyphosate-treated plants. Furthermore, the study evaluates the versatility of two acid-based shikimic acid extraction methods and assesses the longevity of plant extract samples under different storage conditions. Finally, Spec 1 and Spec 2 are further characterized with respect to (1) the capacity to discern between shikimic acid and chemically related alicyclic hydroxy acids, (2) the stability of the chromophore (t1/2), (3) the detection limits, and (4) the cost and simplicity of undertaking the analytical procedure. Overall, spectrophotometric methods were more cost-effective and simpler to execute yet provided a narrower detection limit compared to HPLC. All three methods were specific to shikimic acid and detected the compound in the tissues of glyphosate-susceptible crops, increasing exponentially in concentration within 24 h of glyphosate application and plateauing at approximately 72 h. Spec 1 estimated more shikimic acid in identical plant extract samples compared to Spec 2 and, likewise, HPLC detection was more effective than spectrophotometric determinations. Given the unprecedented global adoption of glyphosate-resistant crops and concomitant use of glyphosate, an effective and accurate assessment of glyphosate efficacy is important. Endogenous shikimic acid determinations are instrumental in corroborating the efficacy of glyphosate and therefore have numerous applications in herbicide research and related areas of science as well as resolving many commercial issues as a consequence of glyphosate utilization.
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Affiliation(s)
- Ian A Zelaya
- Department of Agronomy, Iowa State University, Ames, Iowa 50011-1011, USA.
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Reddy KN, Ding W, Zablotowicz RM, Thomson SJ, Huang Y, Krutz LJ. Biological responses to glyphosate drift from aerial application in non-glyphosate-resistant corn. PEST MANAGEMENT SCIENCE 2010; 66:1148-54. [PMID: 20662010 DOI: 10.1002/ps.1996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 05/21/2010] [Indexed: 05/29/2023]
Abstract
BACKGROUND Glyphosate drift from aerial application onto susceptible crops is inevitable, yet the biological responses to glyphosate drift in crops are not well characterized. The objectives of this research were to determine the effects of glyphosate drift from a single aerial application (18.3 m swath, 866 g AE ha(-1)) on corn injury, chlorophyll content, shikimate level, plant height and shoot dry weight in non-glyphosate-resistant (non-GR) corn. RESULTS One week after application (WAA), corn was killed at 3 m from the edge of the spray swath, with injury decreasing to 18% at 35.4 m downwind. Chlorophyll content decreased from 78% at 6 m to 22% at 15.8 m, and it was unaffected beyond 25.6 m at 1 WAA. Shikimate accumulation in corn decreased from 349% at 0 m to 93% at 15.8 m, and shikimate levels were unaffected beyond 25.6 m downwind. Plant height and shoot dry weight decreased gradually with increasing distance. At a distance of 35.4 m, corn height was reduced by 14% and shoot dry weight by 10% at 3 WAA. CONCLUSIONS Corn injury and other biological responses point to the same conclusion, that is, injury from glyphosate aerial drift is highest at the edge of the spray swath and decreases gradually with distance. The LD(50) (the lethal distance that drift must travel to cause a 50% reduction in biological response) ranged from 12 to 26 m among the biological parameters when wind speed was 11.2 km h(-1) and using a complement of CP-09 spray nozzles on spray aircraft.
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Affiliation(s)
- Krishna N Reddy
- USDA-Agricultural Research Service, Crop Production Systems Research Unit, Stoneville, Mississippi, USA
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Duke SO, Powles SB. Glyphosate: a once-in-a-century herbicide. PEST MANAGEMENT SCIENCE 2008; 64:319-25. [PMID: 18273882 DOI: 10.1002/ps.1518] [Citation(s) in RCA: 748] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 08/09/2007] [Indexed: 05/08/2023]
Abstract
Since its commercial introduction in 1974, glyphosate [N-(phosphonomethyl)glycine] has become the dominant herbicide worldwide. There are several reasons for its success. Glyphosate is a highly effective broad-spectrum herbicide, yet it is very toxicologically and environmentally safe. Glyphosate translocates well, and its action is slow enough to take advantage of this. Glyphosate is the only herbicide that targets 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS), so there are no competing herbicide analogs or classes. Since glyphosate became a generic compound, its cost has dropped dramatically. Perhaps the most important aspect of the success of glyphosate has been the introduction of transgenic, glyphosate-resistant crops in 1996. Almost 90% of all transgenic crops grown worldwide are glyphosate resistant, and the adoption of these crops is increasing at a steady pace. Glyphosate/glyphosate-resistant crop weed management offers significant environmental and other benefits over the technologies that it replaces. The use of this virtually ideal herbicide is now being threatened by the evolution of glyphosate-resistant weeds. Adoption of resistance management practices will be required to maintain the benefits of glyphosate technologies for future generations.
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Affiliation(s)
- Stephen O Duke
- USDA-ARS, Natural Products Utilization Research Unit, National Center for Natural Products Research, PO Box 8048, University, MS 38677, USA.
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Green JM, Hazel CB, Forney DR, Pugh LM. New multiple-herbicide crop resistance and formulation technology to augment the utility of glyphosate. PEST MANAGEMENT SCIENCE 2008; 64:332-9. [PMID: 18069651 DOI: 10.1002/ps.1486] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 06/08/2007] [Indexed: 05/03/2023]
Abstract
Glyphosate has performed long and well, but now some weed communities are shifting to populations that survive glyphosate, and growers need new weed management technologies to augment glyphosate performance in glyphosate-resistant crops. Unfortunately, most companies are not developing any new selective herbicides with new modes of action to fill this need. Fortunately, companies are developing new herbicide-resistant crop technologies to combine with glyphosate resistance and expand the utility of existing herbicides. One of the first multiple-herbicide-resistant crops will have a molecular stack of a new metabolically based glyphosate resistance mechanism with an active-site-based resistance to a broad spectrum of ALS-inhibiting herbicides. Additionally, new formulation technology called homogeneous blends will be used in conjunction with glyphosate and ALS-resistant crops. This formulation technology satisfies governmental regulations, so that new herbicide mixture offerings with diverse modes of action can be commercialized more rapidly and less expensively. Together, homogeneous blends and multiple-herbicide-resistant crops can offer growers a wider choice of herbicide mixtures at rates and ratios to augment glyphosate and satisfy changing weed management needs.
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Affiliation(s)
- Jerry M Green
- Pioneer Hi-Bred International, Stine-Haskell Research Center, Newark, DE 19714-0030, USA.
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