title: Defective copper transport in the copt5 mutant affects cadmium tolerance.
abstract: Cadmium toxicity interferes with essential metal homeostasis, which is a problem for both plant nutrition and the consumption of healthy food by humans. Copper uptake is performed by the members of the Arabidopsis high affinity copper transporter (COPT) family. One of the members, COPT5, is involved in copper recycling from the vacuole toward the cytosolic compartment. We show herein that copt5 mutants are more sensitive to cadmium stress than wild-type plants, as indicated by reduced growth. Exacerbated cadmium toxicity in copt5 mutants is due specifically to altered copper traffic through the COPT5 transporter. Three different processes which have been shown to affect cadmium tolerance are altered in copt5 mutants. First, ethylene biosynthesis diminishes under copper deficiency and, in the presence of cadmium, ethylene production diminishes further. Copper deficiency responses are also attenuated under cadmium treatment. Remarkably, while copt5 roots present higher oxidative stress toxicity symptoms than controls, aerial copt5 parts display lower oxidative stress, as seen by reduced cadmium delivery to shoots. Taken together, these results demonstrate that copper transport plays a key role in cadmium resistance, and suggest that oxidative stress triggers an NADPH oxidase-mediated signaling pathway, which contributes to cadmium translocation and basal plant resistance. The slightly lower cadmium levels that reach aerial parts in the copt5 mutants, irrespective of the copper content in the media, suggest a new biotechnological approach to minimize toxic cadmium entry into food chains.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de València, Av. Doctor Moliner, 5, ES-46100 Burjassot, Valencia, Spain.
authors.forename: Angela
authors.initials: A
authors.lastname: Carrió-Seguí
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de València, Av. Doctor Moliner, 5, ES-46100 Burjassot, Valencia, Spain Present address: Lehrstuhl für Systembiologie der Pflanzen, Technische Universität München-Weihenstephan, Emil-Ramann-Straße, 4, D-85354 Freising, Germany.
authors.forename: Antoni
authors.initials: A
authors.lastname: Garcia-Molina
authors.affiliation: Departament de Biologia Vegetal, Universitat de València, Av. Doctor Moliner, 50, ES-46100 Burjassot, Valencia, Spain.
authors.forename: Amparo
authors.initials: A
authors.lastname: Sanz
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de València, Av. Doctor Moliner, 5, ES-46100 Burjassot, Valencia, Spain penarrub@uv.es.
authors.forename: Lola
authors.initials: L
authors.lastname: Peñarrubia
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D005030:Ethylenes / Q000494:pharmacology; D064527:Etiolation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018546:Hypocotyl / Q000187:drug effects / Q000254:growth & development; D007501:Iron / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D008954:Models, Biological; D009154:Mutation / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects; D063245:Plant Development / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D000080083:SLC31 Proteins; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D015415:Biomarkers; C559588:COPT5 protein, Arabidopsis; D027682:Cation Transport Proteins; D005030:Ethylenes; D000080083:SLC31 Proteins; D002104:Cadmium; D003300:Copper; C036216:ethylene; D007501:Iron
keywords: Arabidopsis thaliana; Cadmium toxicity; Copper transport; Ethylene production; Oxidative stress; copt5 mutants