title: Differential expression and regulation of iron-regulated metal transporters in Arabidopsis halleri and Arabidopsis thaliana--the role in zinc tolerance.
abstract: To avoid zinc (Zn) toxicity, plants have developed a Zn homeostasis mechanism to cope with Zn excess in the surrounding soil. In this report, we uncovered the difference of a cross-homeostasis system between iron (Fe) and Zn in dealing with Zn excess in the Zn hyperaccumulator Arabidopsis halleri ssp. gemmifera and nonhyperaccumulator Arabidopsis thaliana. Arabidopsis halleri shows low expression of the Fe acquisition and deficiency response-related genes IRT1 and IRT2 compared with A. thaliana. In A. thaliana, lowering the expression of IRT1 and IRT2 through the addition of excess Fe to the medium increases Zn tolerance. Excess Zn induces significant Fe deficiency in A. thaliana and reduces Fe accumulation in shoots. By contrast, the accumulation of Fe in shoots of A. halleri was stable under various Zn treatments. Root ferric chelate reductase (FRO) activity and expression of FIT are low in A. halleri compared with A. thaliana. Overexpressing a ZIP family member IRT3 in irt1-1, rescues the Fe-deficient phenotype. A fine-tuned Fe homeostasis mechanism in A. halleri maintains optimum Fe level by Zn-regulated ZIP transporters and prevents high Zn uptake through Fe-regulated metal transporters, and in part be responsible for Zn tolerance.
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, 11529.|Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei, Taiwan, 11529.|Graduate Institute of Biotechnology and Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan, 402.
authors.forename: Varanavasiappan
authors.initials: V
authors.lastname: Shanmugam
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, 11529.|Institute of Plant Biology, National Taiwan University, Taipei, Taiwan 10617.
authors.forename: Jing-Chi
authors.initials: JC
authors.lastname: Lo
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, 11529.
authors.forename: Chia-Lin
authors.initials: CL
authors.lastname: Wu
authors.affiliation: Department of Soil and Environmental Sciences, National Chung-Hsing University, Taichung, Taiwan 402.
authors.forename: Shan-Li
authors.initials: SL
authors.lastname: Wang
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, 11529.
authors.forename: Chong-Cheong
authors.initials: CC
authors.lastname: Lai
authors.affiliation: Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Erin L
authors.initials: EL
authors.lastname: Connolly
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, 11529.
authors.forename: Jing-Ling
authors.initials: JL
authors.lastname: Huang
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, 11529.|Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei, Taiwan, 11529.|Graduate Institute of Biotechnology and Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan, 402.
authors.forename: Kuo-Chen
authors.initials: KC
authors.lastname: Yeh
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects* / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D038181:FMN Reductase / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D007501:Iron / Q000494:pharmacology*; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D015032:Zinc / Q000633:toxicity*
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D027682:Cation Transport Proteins; D038181:FMN Reductase; D007501:Iron; D026901:Membrane Transport Proteins; D010940:Plant Proteins; D015032:Zinc; C501411:FIT1 protein, Arabidopsis; C099651:IRT1 protein, Arabidopsis; C434452:IRT2 protein, Arabidopsis; C023903:ferric citrate iron reductase