title: Engineered silver nanoparticles are sensed at the plasma membrane and dramatically modify the physiology of Arabidopsis thaliana plants.
abstract: Silver nanoparticles (Ag NPs) are the world's most important nanomaterial and nanotoxicant. The aim of this study was to determine the early stages of interactions between Ag NPs and plant cells, and to investigate their physiological roles. We have shown that the addition of Ag NPs to cultivation medium, at levels above 300 mg L(-1) , inhibited Arabidopsis thaliana root elongation and leaf expansion. This also resulted in decreased photosynthetic efficiency and the extreme accumulation of Ag in tissues. Acute application of Ag NPs induced a transient elevation of [Ca(2+) ]cyt and the accumulation of reactive oxygen species (ROS; partially generated by NADPH oxidase). Whole-cell patch-clamp measurements on root cell protoplasts demonstrated that Ag NPs slightly inhibited plasma membrane K(+) efflux and Ca(2+) influx currents, or caused membrane breakdown; however, in excised outside-out patches, Ag NPs activated Gd(3+) -sensitive Ca(2+) influx channels with unitary conductance of approximately 56 pS. Bulk particles did not modify the plasma membrane currents. Tests with electron paramagnetic resonance spectroscopy showed that Ag NPs were not able to catalyse hydroxyl radical generation, but that they directly oxidized the major plant antioxidant, l-ascorbic acid. Overall, the data presented shed light on mechanisms of the impact of nanosilver on plant cells, and show that these include the induction of classical stress signalling reactions (mediated by [Ca(2+) ]cyt and ROS) and a specific effect on the plasma membrane conductance and the reduced ascorbate.
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK.
authors.forename: Arifa
authors.initials: A
authors.lastname: Sosan
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Svistunenko
authors.affiliation: Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus.
authors.forename: Darya
authors.initials: D
authors.lastname: Straltsova
authors.affiliation: Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus.
authors.forename: Katsiaryna
authors.initials: K
authors.lastname: Tsiurkina
authors.affiliation: Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus.
authors.forename: Igor
authors.initials: I
authors.lastname: Smolich
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK.
authors.forename: Tracy
authors.initials: T
authors.lastname: Lawson
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK.
authors.forename: Sunitha
authors.initials: S
authors.lastname: Subramaniam
authors.affiliation: Department of Chemistry, The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, 8041, New Zealand.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Golovko
authors.affiliation: Department of Chemistry, The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, 8041, New Zealand.
authors.forename: David
authors.initials: D
authors.lastname: Anderson
authors.affiliation: Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus.
authors.forename: Anatoliy
authors.initials: A
authors.lastname: Sokolik
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Colbeck
authors.affiliation: Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Square, Minsk, 220030, Belarus.|Russian Academy of Sciences, Komarov Botanical Institute, 2 Professora Popova Street, 197376, St.-Petersburg, Russia.
authors.forename: Vadim
authors.initials: V
authors.lastname: Demidchik
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012834:Silver / Q000737:chemistry*
chemical_list: D007473:Ion Channels; D017382:Reactive Oxygen Species; D012834:Silver; D001205:Ascorbic Acid; D002118:Calcium
keywords: Arabidopsis thaliana; ascorbic acid; cell calcium; ion channels; reactive oxygen species; silver nanoparticles; stress signalling