title: Oxidative stress in duckweed (Lemna minor L.) induced by glyphosate: Is the mitochondrial electron transport chain a target of this herbicide?
abstract: We investigated the physiological responses of Lemna minor plants exposed to glyphosate. The deleterious effects of this herbicide on photosynthesis, respiration, and pigment concentrations were related to glyphosate-induced oxidative stress through hydrogen peroxide (H2O2) accumulation. By using photosynthetic and respiratory electron transport chain (ETC) inhibitors we located the primary site of reactive oxygen species (ROS) production in plants exposed to 500 mg glyphosate l-1. Inhibition of mitochondrial ETC Complex I by rotenone reduced H2O2concentrations in glyphosate-treated plants. Complex III activity was very sensitive to glyphosate which appears to act much like antimycin A (an inhibitor of mitochondrial ETC Complex III) by shunting electrons from semiquinone to oxygen, with resulting ROS formation. Confocal evaluations for ROS localization showed that ROS are initially produced outside of the chloroplasts upon initial glyphosate exposure. Our results indicate that in addition to interfering with the shikimate pathway, glyphosate can induce oxidative stress in plants through H2O2formation by targeting the mitochondrial ETC, which would explain its observed effects on non-target organisms.
authors.affiliation: Université du Québec à Montréal, Department of Biological Sciences, GRIL - TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Succ. Centre-Ville, H3C 3P8, Montréal, Québec, Canada. Electronic address: marcelopgom@gmail.com.
authors.forename: Marcelo Pedrosa
authors.initials: MP
authors.lastname: Gomes
authors.affiliation: Université du Québec à Montréal, Department of Biological Sciences, GRIL - TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Succ. Centre-Ville, H3C 3P8, Montréal, Québec, Canada. Electronic address: juneau.philippe@uqam.ca.
authors.forename: Philippe
authors.initials: P
authors.lastname: Juneau
mesh_terms: D000968:Antimycin A / Q000494:pharmacology; D029064:Araceae / Q000187:drug effects* / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects*; D045222:Electron Transport Chain Complex Proteins / Q000037:antagonists & inhibitors; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006540:Herbicides / Q000633:toxicity*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010788:Photosynthesis / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology; D000097797:Glyphosate
chemical_list: D000968:Antimycin A; D045222:Electron Transport Chain Complex Proteins; D005998:Glycine; D006540:Herbicides; D006861:Hydrogen Peroxide; D017382:Reactive Oxygen Species; D012402:Rotenone; D000097797:Glyphosate
keywords: Herbicide; Oxidative stress; Respiration; Shikimate; Toxicity