title: Differential response of Arabidopsis leaves and roots to cadmium: glutathione-related chelating capacity vs antioxidant capacity.
abstract: This study aims to uncover the spatiotemporal involvement of glutathione (GSH) in two major mechanisms of cadmium (Cd)-induced detoxification (i.e. chelation and antioxidative defence). A kinetic study was conducted on hydroponically grown Arabidopsis thaliana (L. Heyhn) to gain insight into the early events after exposure to Cd. Cadmium detoxification was investigated at different levels, including gene transcripts, enzyme activities and metabolite content. Data indicate a time-dependent response both within roots and between plant organs. Early on in roots, GSH was preferentially allocated to phytochelatin (PC) synthesis destined for Cd chelation. This led to decreased GSH levels, without alternative pathways activated to complement GSH's antioxidative functions. After one day however, multiple antioxidative pathways increased including superoxide dismutase (SOD), ascorbate (AsA) and catalase (CAT) to ensure efficient neutralization of Cd-induced reactive oxygen species (ROS). As a consequence of Cd retention and detoxification in roots, a delayed response occurred in leaves. Together with high leaf thiol contents and possibly signalling responses from the roots, the leaves were protected, allowing them sufficient time to activate their defence mechanisms.
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: marijke.jozefczak@uhasselt.be.
authors: Marijke
authors: M
authors: Jozefczak
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: els.keunen@uhasselt.be.
authors: Els
authors: E
authors: Keunen
authors: Free University of Amsterdam, Institute of Molecular and Cellular Biology, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands. Electronic address: h.schat@vu.nl.
authors: Henk
authors: H
authors: Schat
authors: Free University of Amsterdam, Institute of Molecular and Cellular Biology, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands. Electronic address: m.bliek@vu.nl.
authors: Mattijs
authors: M
authors: Bliek
authors: Universidad Autónoma de Madrid, Laboratorio de Fisiología Vegetal, Departamento de Biología, Campus de Cantoblanco, 28049 Madrid, Spain. Electronic address: luise.hernandez@uam.es.
authors: Luis E
authors: LE
authors: Hernández
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: robert.carleer@uhasselt.be.
authors: Robert
authors: R
authors: Carleer
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: tony.remans@uhasselt.be.
authors: Tony
authors: T
authors: Remans
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: sacha.bohler@uhasselt.be.
authors: Sacha
authors: S
authors: Bohler
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: jaco.vangronsveld@uhasselt.be.
authors: Jaco
authors: J
authors: Vangronsveld
authors: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium. Electronic address: ann.cuypers@uhasselt.be.
authors: Ann
authors: A
authors: Cuypers
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D005978:Glutathione / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D013438:Sulfhydryl Compounds; D002104:Cadmium; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D005978:Glutathione
keywords: Antioxidative defence; Arabidopsis; Cadmium; Chelation; Glutathione; Phytochelatins