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Lupwayi NZ, Blackshaw RE, Geddes CM, Dunn R, Petri RM. Multi-year and multi-site effects of recurrent glyphosate applications on the wheat rhizosphere microbiome. ENVIRONMENTAL RESEARCH 2022; 215:114363. [PMID: 36174759 DOI: 10.1016/j.envres.2022.114363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Glyphosate (N-(phosphonomethyl)glycine) is broad-spectrum herbicide that is extensively used worldwide, but its effects on the soil microbiome are inconsistent. To provide a sound scientific basis for herbicide re-review and registration decisions, we conducted a four-year (2013-2016) study in which we consecutively applied glyphosate to a wheat (Triticum aestivum L.)-field pea (Pisum sativum L.)-canola (Brassica napus L.)-wheat crop rotation at five sites in the Canadian prairies. The glyphosate rates were 0, 1, 2, 4 and 8 kg ae ha-1, applied pre-seeding and post-harvest every year. The wheat rhizosphere was sampled in the final year of the study and analysed for microbial biomass C (MBC), the composition and diversity of the microbiome, and activities of β-glucosidase, N-acetyl-β-glucosiminidase, acid phosphomonoesterase and arylsulphatase. Glyphosate did not affect MBC, the composition and diversity of prokaryotes and fungi, and the activities of three of the four enzymes measured in the wheat rhizosphere. The one effect of glyphosate was a wave-like response of N-acetyl-β-glucosaminidase activity with increasing application rates. The experimental sites had much greater effects, driven by soil pH and organic C, on the soil microbiome composition and enzyme activities than glyphosate. Soil pH was positively correlated with the relative abundance of Acidobacteriota but negatively correlated with that of Actinobacteriota and Basidiomycota. Soil organic C was positively correlated with the relative abundances of Proteobacteriota and Verrucomicrobiota, but negatively correlated with the relative abundance of Crenachaeota. The activity of acid phosphomonoesterase declined with increasing relative abundance of Acidobacteriota, but increased with that of Actinobacteriota and Basidiomycota. The activity of N-acetyl-β-glucosaminidase also increased with increasing relative abundance of Actinobacteriota but decreased with that of Mortierellomycota. β-glucosidase activity also decreased with increasing relative abundance of Mortierellomycota. The core fungal species observed in at least 90% of the samples were Humicola nigrescens, Gibberella tricincta and Giberella fujikuroi. Therefore, this multi-site study on the Canadian prairies revealed no significant effects of 4-year applications of glyphosate applied at different rates on most soil microbial properties despite differences in the properties among sites. However, it is important to keep evaluating glyphosate effects on the soil microbiome and its functioning because it is the most widely used herbicide worldwide.
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Affiliation(s)
- Newton Z Lupwayi
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, Alberta, T1J 4B1, Canada.
| | - Robert E Blackshaw
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, Alberta, T1J 4B1, Canada
| | - Charles M Geddes
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, Alberta, T1J 4B1, Canada
| | - Rob Dunn
- FarmWise Inc., Lethbridge, Alberta, Canada
| | - Renee M Petri
- Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, 2000 College Street, Sherbrooke, Quebec, J1M 0C8, Canada
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2
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Wee J, Lee YS, Kim Y, Lee YH, Lee SE, Hyun S, Cho K. Multigeneration toxicity of Geunsami® (a glyphosate-based herbicide) to Allonychiurus kimi (Lee) (Collembola) from sub-individual to population levels. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 291:118172. [PMID: 34543960 DOI: 10.1016/j.envpol.2021.118172] [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] [Received: 05/21/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Glyphosate-based herbicide (GBH) is the most widely used herbicide worldwide and has long been considered to have significantly low toxicity to non-target soil invertebrates based on short-term toxicity tests (<56 d). However, long-term GBH toxicity assessment is necessary as GBH is repeatedly applied in the same field annually because of the advent of glyphosate-resistant crops. In this study, a multigeneration test was conducted where Allonychiurus kimi (Collembola) was exposed to GBH for three generations (referred to as F0, F1, and F2) to evaluate the long-term toxic effect. The endpoints used were adult survival and juvenile production for the individual level toxicity assessment. Phospholipid profile and population age structure were the endpoints used for sub-individual and population levels, respectively. GBH was observed to have no negative effects on adult survivals of all generations, but juvenile production was found to decrease in a concentration-dependent manner, with EC50s being estimated as 572.5, 274.8, and 59.8 mg a.i. kg-1 in the F0, F1, and F2 generations, respectively. The age structure of A. kimi population produced in the test of all generations was altered by GBH exposure, mainly because of the decrease in the number of young juveniles. Further, differences between the phospholipid profiles of the control and GBH treatments became apparent over generations, with PA 16:0, PA 12:0, and PS 42:0 lipids not being detected at the highest concentration of 741 mg kg-1 in F2. Considering all our findings from sub-individual to population levels, repeated and long-term use of GBH could have significantly higher negative impacts on non-target soil organisms than expected.
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Affiliation(s)
- June Wee
- O-Jeong Eco-Resilience Institute, Korea University, Seoul, 02841, Republic of Korea
| | - Yun-Sik Lee
- O-Jeong Eco-Resilience Institute, Korea University, Seoul, 02841, Republic of Korea
| | - Yongeun Kim
- O-Jeong Eco-Resilience Institute, Korea University, Seoul, 02841, Republic of Korea
| | - Yong Ho Lee
- O-Jeong Eco-Resilience Institute, Korea University, Seoul, 02841, Republic of Korea; Institute of Ecological Phytochemistry, Hankyong National University, Ansung, 17579, Republic of Korea
| | - Sung-Eun Lee
- Department of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Seunghun Hyun
- Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Kijong Cho
- Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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3
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Allegrini M, Morales ME, Villamil MB, Zabaloy MC. Ammonia Oxidizing Prokaryotes Respond Differently to Fertilization and Termination Methods in Common Oat's Rhizosphere. Front Microbiol 2021; 12:746524. [PMID: 34690996 PMCID: PMC8527175 DOI: 10.3389/fmicb.2021.746524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Cover crops (CC) have demonstrated beneficial effects on several soil properties yet questions remain regarding their effects on soil microbial communities. Among them, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) have a key role for N cycling in soil and their responses in the rhizosphere of terminated CC deserve further investigation. A greenhouse experiment was established to assess N fertilization (with or without N) and termination methods (glyphosate, mowing, and untreated control) of common oat (Avena sativa L.) as potential drivers of AOA and AOB responses in the rhizosphere. The abundance of amoA genes was determined by quantitative real-time PCR (qPCR), the community structure was assessed with Illumina amplicon sequencing of these genes, while the function was assessed from potential nitrification activity (PNA). While N fertilization had no influence on AOA, the termination method significantly increased amoA gene copies of AOA in mowed plants relative to glyphosate termination or the untreated control (1.76 and 1.49-fold change, respectively), and shifted AOA community structure (PERMANOVA, p<0.05). Ordination methods indicated a separation between AOA communities from control and glyphosate-terminated plants relative to mowed plants for both UniFrac and Aitchison distance. Converserly, N fertilization significantly increased AOB abundance in the rhizosphere of mowed and control plants, yet not in glyphosate-treated plants. Analyses of community structure showed that AOB changed only in response to N fertilization and not to the termination method. In line with these results, significantly higher PNA values were measured in all fertilized samples, regardless of the termination methods. Overall, the results of this study indicated that bacterial and archaeal nitrifiers have contrasting responses to fertlization and plant termination methods. While AOA were responsive to the termination method, AOB were more sensitive to N additions, although, the stimulative effect of N fertilization on amoAAOB abundance was dependent on the termination method.
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Affiliation(s)
- Marco Allegrini
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Marianela E Morales
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur (UNS)-CONICET, Bahía Blanca, Argentina
| | - Maria B Villamil
- Department of Crop Sciences, University of Illinois, Urbana, IL, United States
| | - María Celina Zabaloy
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur (UNS)-CONICET, Bahía Blanca, Argentina.,Departamento de Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina
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Vázquez MB, Moreno MV, Amodeo MR, Bianchinotti MV. Effects of glyphosate on soil fungal communities: A field study. Rev Argent Microbiol 2021; 53:349-358. [PMID: 33551324 DOI: 10.1016/j.ram.2020.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/28/2020] [Accepted: 10/29/2020] [Indexed: 11/24/2022] Open
Abstract
The driving forces behind many soil processes are microorganisms and they are able to respond immediately to environmental changes. The soil microbial community impacts on many soil properties. More than one-third of the terrestrial ecosystems are semiarid. However, a limited number of studies have been conducted to characterize soil fungal communities in semiarid grasslands, in particular those of agricultural fields. The aim of this study was to explore changes in the diversity and structure of soil fungal communities in semiarid grasslands, after different doses of glyphosate were applied under field conditions. Changes in soil fungal communities were examined using different approaches including culturing, calcofluor white stain and denaturing gradient gel electrophoresis (DGGE). The different approaches complement each other, revealing different aspects of the effect of glyphosate on soil fungal communities. We demonstrated a negative effect of glyphosate on soil fungal biomass at high doses and an early and transitory stimulatory effect on soil fungal biomass. We also found a negative effect of glyphosate on the species richness of cultivable fungi and changes in the molecular structure of soil fungal communities after double doses or long-term glyphosate application. In summary, our findings demonstrate an overall negative effect of glyphosate on soil fungal communities.
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Affiliation(s)
- María Belén Vázquez
- CERZOS-CONICET, CCT Bahía Blanca, Camino La Carrindanga km 7, Bahía Blanca CP B8000FWB, Argentina.
| | - María Virginia Moreno
- Laboratorio de Biología Funcional y Biotecnología (BIOLAB) INBIOTEC-CONICET-CICBA, Facultad de Agronomía, UNCPBA, República de Italia 780, Azul, CP 7300, Argentina
| | - Martín Raúl Amodeo
- GEKKO-CONICET, UNIVERSIDAD NACIONAL DEL SUR, San Juan 670, Bahía Blanca, CP B8000, Argentina
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Billenkamp F, Schnabel K, Hüther L, Frahm J, von Soosten D, Meyer U, Höper D, Beer M, Seyboldt C, Neubauer H, Dänicke S. No hints at glyphosate-induced ruminal dysbiosis in cows. NPJ Biofilms Microbiomes 2021; 7:30. [PMID: 33767196 PMCID: PMC7994389 DOI: 10.1038/s41522-021-00198-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/12/2021] [Indexed: 01/31/2023] Open
Abstract
Glyphosate-based herbicides are among the most used non-selective herbicides worldwide and inhibit synthesis of aromatic amino acids in plants, bacteria, and fungi. Given the broad usage, controversies concerning potential effects of glyphosate on health and especially on gut microbiomes arose. For cattle, it has been proposed based on in vitro data that glyphosate has detrimental effects on the ruminal microbiome, which manifest as a specific inhibition of bacteria involved in fiber degradation and as an enrichment of specific pathogens. In the present study, glyphosate effects on the ruminal microbiome were analyzed in vivo using glyphosate contaminated feedstuffs with strong differences in dietary fiber and dietary energy content in order to reproduce the proposed detrimental glyphosate effects on the rumen microbiome. While significant impact of dietary factors on the ruminal microbiome and its products are pointed out, no adverse glyphosate effects on ruminal microbiome composition, diversity, and microbial metabolites are observed.
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Affiliation(s)
- Fabian Billenkamp
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany.
| | - Karina Schnabel
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany
| | - Liane Hüther
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany
| | - Jana Frahm
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany
| | - Dirk von Soosten
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany
| | - Ulrich Meyer
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany
| | - Dirk Höper
- Institute of Diagnostic Virology, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Greifswald-Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Greifswald-Riems, Germany
| | - Christian Seyboldt
- Institute of Bacterial Infections and Zoonoses, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Jena, Germany
| | - Heinrich Neubauer
- Institute of Bacterial Infections and Zoonoses, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Jena, Germany
| | - Sven Dänicke
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institute, Brunswick, Germany
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6
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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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7
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Morgan MA, Griffith CM, Dinges MM, Lyon YA, Julian RR, Larive CK. Evaluating sub-lethal stress from Roundup ® exposure in Artemia franciscana using 1H NMR and GC-MS. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 212:77-87. [PMID: 31077969 PMCID: PMC6581565 DOI: 10.1016/j.aquatox.2019.04.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 05/04/2023]
Abstract
Global salinization trends present an urgent need for methods to monitor aquatic ecosystem health and characterize known and emerging stressors for water bodies that are becoming increasingly saline. Environmental metabolomics methods that combine quantitative measurements of metabolite levels and multivariate statistical analysis are powerful tools for ascertaining biological impacts and identifying potential biomarkers of exposure. We propose the use of the saltwater aquatic crustacean, Artemia franciscana, as a model organism for environmental metabolomics in saltwater ecosystems. Artemia are a good choice for ecotoxicity assays and metabolomics analysis because they have a short life cycle, their hemolymph is rich in metabolites and they tolerate a wide salinity range. In this work we explore the potential of Artemia franciscana for environmental metabolomics through exposure to the broad-spectrum herbicide, glyphosate. The LC50 for a 48 h exposure of Roundup® was determined to be 237 ± 23 ppm glyphosate in the Roundup® formulation. Artemia cysts were hatched and exposed to sub-lethal glyphosate concentrations of 1.00, 10.0, 50.0, or 100 ppm glyphosate in Roundup®. We profiled 48 h old Artemia extracts using 1H NMR and GC-MS. Dose-dependent metabolic perturbation was evident for several metabolites using univariate and multivariate analyses. Metabolites significantly affected by Roundup® exposure included aspartate, formate, betaine, glucose, tyrosine, phenylalanine, gadusol, and isopropylamine. Biochemical pathway analysis with the KEGG database suggests impairment of carbohydrate and energy metabolism, folate-mediated one-carbon metabolism, Artemia molting and development, and microbial metabolism.
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Affiliation(s)
- Melissa A Morgan
- Department of Chemistry, University of California - Riverside, Riverside, CA, 92521, United States
| | - Corey M Griffith
- Environmental Toxicology Graduate Program, University of California - Riverside, Riverside, CA, 92521, United States
| | - Meredith M Dinges
- Department of Chemistry, University of California - Riverside, Riverside, CA, 92521, United States
| | - Yana A Lyon
- Department of Chemistry, University of California - Riverside, Riverside, CA, 92521, United States
| | - Ryan R Julian
- Department of Chemistry, University of California - Riverside, Riverside, CA, 92521, United States
| | - Cynthia K Larive
- Department of Chemistry, University of California - Riverside, Riverside, CA, 92521, United States.
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8
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Van Bruggen AHC, He MM, Shin K, Mai V, Jeong KC, Finckh MR, Morris JG. Environmental and health effects of the herbicide glyphosate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:255-268. [PMID: 29117584 DOI: 10.1016/j.scitotenv.2017.10.309] [Citation(s) in RCA: 393] [Impact Index Per Article: 65.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/29/2017] [Accepted: 10/29/2017] [Indexed: 05/28/2023]
Abstract
The herbicide glyphosate, N-(phosphonomethyl) glycine, has been used extensively in the past 40years, under the assumption that side effects were minimal. However, in recent years, concerns have increased worldwide about the potential wide ranging direct and indirect health effects of the large scale use of glyphosate. In 2015, the World Health Organization reclassified glyphosate as probably carcinogenic to humans. A detailed overview is given of the scientific literature on the movement and residues of glyphosate and its breakdown product aminomethyl phosphonic acid (AMPA) in soil and water, their toxicity to macro- and microorganisms, their effects on microbial compositions and potential indirect effects on plant, animal and human health. Although the acute toxic effects of glyphosate and AMPA on mammals are low, there are animal data raising the possibility of health effects associated with chronic, ultra-low doses related to accumulation of these compounds in the environment. Intensive glyphosate use has led to the selection of glyphosate-resistant weeds and microorganisms. Shifts in microbial compositions due to selective pressure by glyphosate may have contributed to the proliferation of plant and animal pathogens. Research on a link between glyphosate and antibiotic resistance is still scarce but we hypothesize that the selection pressure for glyphosate-resistance in bacteria could lead to shifts in microbiome composition and increases in antibiotic resistance to clinically important antimicrobial agents. We recommend interdisciplinary research on the associations between low level chronic glyphosate exposure, distortions in microbial communities, expansion of antibiotic resistance and the emergence of animal, human and plant diseases. Independent research is needed to revisit the tolerance thresholds for glyphosate residues in water, food and animal feed taking all possible health risks into account.
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Affiliation(s)
- A H C Van Bruggen
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA; Department of Plant Pathology, IFAS, University of Florida, Gainesville, FL 32610, USA.
| | - M M He
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA; Department of Life and Environment Science, Hangzhou Normal University, Zhejiang 310036, China
| | - K Shin
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA; Department of Plant Pathology, IFAS, University of Florida, Gainesville, FL 32610, USA
| | - V Mai
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA
| | - K C Jeong
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA
| | - M R Finckh
- Faculty of Organic Agricultural Sciences, Ecological Plant Protection, University of Kassel, 37213 Witzenhausen, Germany
| | - J G Morris
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA; Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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Impacts of Repeated Glyphosate Use on Wheat-Associated Bacteria Are Small and Depend on Glyphosate Use History. Appl Environ Microbiol 2017. [PMID: 28864656 DOI: 10.1128/aem.01354‐17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glyphosate is the most widely used herbicide worldwide and a critical tool for weed control in no-till cropping systems. However, there are concerns about the nontarget impacts of long-term glyphosate use on soil microbial communities. We investigated the impacts of repeated glyphosate treatments on bacterial communities in the soil and rhizosphere of wheat in soils with and without long-term history of glyphosate use. We cycled wheat in the greenhouse using soils from 4 paired fields under no-till (20+-year history of glyphosate) or no history of use. At each cycle, we terminated plants with glyphosate (2× the field rate) or by removing the crowns, and soil and rhizosphere bacterial communities were characterized. Location, cropping history, year, and proximity to the roots had much stronger effects on bacterial communities than did glyphosate, which only explained 2 to 5% of the variation. Less than 1% of all taxa were impacted by glyphosate, more in soils with a long history of use, and more increased than decreased in relative abundance. Glyphosate had minimal impacts on soil and rhizosphere bacteria of wheat, although dying roots after glyphosate application may provide a "greenbridge" favoring some copiotrophic taxa.IMPORTANCE Glyphosate (Roundup) is the most widely used herbicide in the world and the foundation of Roundup Ready soybeans, corn, and the no-till cropping system. However, there have been recent concerns about nontarget impacts of glyphosate on soil microbes. Using next-generation sequencing methods and glyphosate treatments of wheat plants, we described the bacterial communities in the soil and rhizosphere of wheat grown in Pacific Northwest soils across multiple years, different locations, and soils with different histories of glyphosate use. The effects of glyphosate were subtle and much less than those of drivers such as location and cropping systems. Only a small percentage of the bacterial groups were influenced by glyphosate, and most of those were stimulated, probably because of the dying roots. This study provides important information for the future of this important tool for no-till systems and the environmental benefits of reducing soil erosion and fossil fuel inputs.
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10
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Schlatter DC, Yin C, Hulbert S, Burke I, Paulitz T. Impacts of Repeated Glyphosate Use on Wheat-Associated Bacteria Are Small and Depend on Glyphosate Use History. Appl Environ Microbiol 2017; 83:e01354-17. [PMID: 28864656 PMCID: PMC5666137 DOI: 10.1128/aem.01354-17] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/30/2017] [Indexed: 02/01/2023] Open
Abstract
Glyphosate is the most widely used herbicide worldwide and a critical tool for weed control in no-till cropping systems. However, there are concerns about the nontarget impacts of long-term glyphosate use on soil microbial communities. We investigated the impacts of repeated glyphosate treatments on bacterial communities in the soil and rhizosphere of wheat in soils with and without long-term history of glyphosate use. We cycled wheat in the greenhouse using soils from 4 paired fields under no-till (20+-year history of glyphosate) or no history of use. At each cycle, we terminated plants with glyphosate (2× the field rate) or by removing the crowns, and soil and rhizosphere bacterial communities were characterized. Location, cropping history, year, and proximity to the roots had much stronger effects on bacterial communities than did glyphosate, which only explained 2 to 5% of the variation. Less than 1% of all taxa were impacted by glyphosate, more in soils with a long history of use, and more increased than decreased in relative abundance. Glyphosate had minimal impacts on soil and rhizosphere bacteria of wheat, although dying roots after glyphosate application may provide a "greenbridge" favoring some copiotrophic taxa.IMPORTANCE Glyphosate (Roundup) is the most widely used herbicide in the world and the foundation of Roundup Ready soybeans, corn, and the no-till cropping system. However, there have been recent concerns about nontarget impacts of glyphosate on soil microbes. Using next-generation sequencing methods and glyphosate treatments of wheat plants, we described the bacterial communities in the soil and rhizosphere of wheat grown in Pacific Northwest soils across multiple years, different locations, and soils with different histories of glyphosate use. The effects of glyphosate were subtle and much less than those of drivers such as location and cropping systems. Only a small percentage of the bacterial groups were influenced by glyphosate, and most of those were stimulated, probably because of the dying roots. This study provides important information for the future of this important tool for no-till systems and the environmental benefits of reducing soil erosion and fossil fuel inputs.
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Affiliation(s)
- Daniel C Schlatter
- USDA-ARS, Wheat Health, Genetics and Quality Research Unit, Pullman, Washington, USA
| | - Chuntao Yin
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA
| | - Scot Hulbert
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA
| | - Ian Burke
- Department of Crop and Soil Sciences, Washington State University, Pullman, Washington, USA
| | - Timothy Paulitz
- USDA-ARS, Wheat Health, Genetics and Quality Research Unit, Pullman, Washington, USA
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11
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Tsatsakis AM, Nawaz MA, Kouretas D, Balias G, Savolainen K, Tutelyan VA, Golokhvast KS, Lee JD, Yang SH, Chung G. Environmental impacts of genetically modified plants: A review. ENVIRONMENTAL RESEARCH 2017; 156:818-833. [PMID: 28347490 DOI: 10.1016/j.envres.2017.03.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 06/06/2023]
Abstract
Powerful scientific techniques have caused dramatic expansion of genetically modified crops leading to altered agricultural practices posing direct and indirect environmental implications. Despite the enhanced yield potential, risks and biosafety concerns associated with such GM crops are the fundamental issues to be addressed. An increasing interest can be noted among the researchers and policy makers in exploring unintended effects of transgenes associated with gene flow, flow of naked DNA, weediness and chemical toxicity. The current state of knowledge reveals that GM crops impart damaging impacts on the environment such as modification in crop pervasiveness or invasiveness, the emergence of herbicide and insecticide tolerance, transgene stacking and disturbed biodiversity, but these impacts require a more in-depth view and critical research so as to unveil further facts. Most of the reviewed scientific resources provide similar conclusions and currently there is an insufficient amount of data available and up until today, the consumption of GM plant products are safe for consumption to a greater extent with few exceptions. This paper updates the undesirable impacts of GM crops and their products on target and non-target species and attempts to shed light on the emerging challenges and threats associated with it. Underpinning research also realizes the influence of GM crops on a disturbance in biodiversity, development of resistance and evolution slightly resembles with the effects of non-GM cultivation. Future prospects are also discussed.
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Affiliation(s)
- Aristidis M Tsatsakis
- Department of Toxicology and Forensics, School of Medicine, University of Crete, Heraklion, Crete, Greece; Educational Scientific Center of Nanotechnology, Far Eastern Federal University, Vladivostok 690950, Russian Federation
| | - Muhammad Amjad Nawaz
- Department of Biotechnology, Chonnam National University, Yeosu, Chonnam 59626, Republic of Korea
| | - Demetrios Kouretas
- Department of Biochemistry-Biotechnology, University of Thessaly, Larisa, Greece
| | | | - Kai Savolainen
- Finnish Institute of Occupational Health, POB 40 Helsinki, Finland
| | - Victor A Tutelyan
- Federal Research Centre of Nutrition, Biotechnology and Food Safety, Moscow, Russian Federation
| | - Kirill S Golokhvast
- Educational Scientific Center of Nanotechnology, Far Eastern Federal University, Vladivostok 690950, Russian Federation; Pacific Institute of Geography, FEB RAS, Vladivostok 690041, Russian Federation
| | - Jeong Dong Lee
- School of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Seung Hwan Yang
- Department of Biotechnology, Chonnam National University, Yeosu, Chonnam 59626, Republic of Korea
| | - Gyuhwa Chung
- Department of Biotechnology, Chonnam National University, Yeosu, Chonnam 59626, Republic of Korea.
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