title: Cd-induced Cu deficiency responses in Arabidopsis thaliana: are phytochelatins involved?
abstract: Cadmium (Cd) exposure can disturb the homeostasis of essential elements. In Arabidopsis thaliana, Cd induces a squamosa promoter binding protein-like 7 (SPL7)-dependent Cu deficiency response. We investigated how Cd induces a Cu deficiency response. The Cu deficiency response consists of the active SPL7 transcription factor binding to GTAC motifs in promoters of among others several Cu transporters, a Cu chaperone, and cupro-miRNAs to regulate Cu homeostasis. We demonstrated that the addition of supplemental Cu to Cd-exposed A. thaliana plants diminished the Cu deficiency response in roots, while it even disappeared in leaves. Exposure of plants to Cd in combination with extra Cu reduced Cd levels in both roots and leaves resulting in an improved cellular oxidative state. Furthermore, we demonstrated a role for phytochelatins (PCs) in the Cd-induced Cu deficiency response, because it was reduced in roots of cad1-3 mutant plants exposed to Cd. In conclusion, a working mechanism is provided in which it is suggested that Cd increases PC levels that can complex both Cd and Cu. This results in cellular Cu deficiency and subsequently the activation of SPL7 and hence the induction of the Cu deficiency response.
authors.affiliation: Environmental Biology, Centre for Environmental Sciences, Hasselt University, B-3590, Diepenbeek, Belgium.
authors.forename: Heidi
authors.initials: H
authors.lastname: Gielen
authors.affiliation: Environmental Biology, Centre for Environmental Sciences, Hasselt University, B-3590, Diepenbeek, Belgium.
authors.forename: Jaco
authors.initials: J
authors.lastname: Vangronsveld
authors.affiliation: Environmental Biology, Centre for Environmental Sciences, Hasselt University, B-3590, Diepenbeek, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Cuypers
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D018533:Biomass; D002104:Cadmium / Q000494:pharmacology*; D003300:Copper / Q000172:deficiency*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D026901:Membrane Transport Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D054811:Phytochelatins / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; D002104:Cadmium; D003300:Copper; D054811:Phytochelatins
keywords: Arabidopsis; Cu homeostasis; SPL7; cadmium; copper; metal stress; phytochelatins