The Arabidopsis thaliana AtHMA3 protein belongs to the P1B-2 subgroup of the P-type ATPase family, which is involved in heavy metal transport. In a previous study, we have shown, using heterologous expression in the yeast Saccharomyces cerevisiae, that in the presence of toxic metals, AtHMA3 was able to phenotypically complement the Cd/Pb hypersensitive strain ycf1, but not the Zn hypersensitive strain zrc1. In the present study, we demonstrate that AtHMA3 in planta is located to the vacuolar membrane, with a high expression level in guard cells, hydathodes, vascular tissues and the root apex. Confocal imaging in the presence of the Zn/Cd fluorescent probe BTC-5N revealed that AtHMA3 participates in the vacuolar storage of Cd. A T-DNA insertional mutant was found more sensitive to Zn and Cd. Conversely, ectopic overexpression of AtHMA3 improved plant tolerance to Cd, Co, Pb, and Zn; Cd accumulation increased by about two to three-fold in plants overexpressing AtHMA3 compared to wild-type plants. Thus, AtHMA3 likely plays a role in the detoxification of biological (Zn) and non biological heavy metals (Cd, Co and Pb) by participating in their vacuolar sequestration, an original function for a P1B-2 ATPase in a multicellular eukaryote.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|