Fe homeostasis based Zn tolerance in the Zn/Cd hyperaccumulator A. halleri

To avoid Zn toxicity, plants have developed a zinc (Zn) homeostasis mechanism to cope with Zn excess in the surrounding soil. We investigated a cross-homeostasis system of iron (Fe) and Zn in dealing with Zn excess in the Zn hyperaccumulator Arabidopsis halleri ssp. gemmifera and non-hyperaccumulator Arabidopsis thaliana. We found that excess Zn induced significant Fe deficiency in A. thaliana, but not in A. halleri. In A. halleri, the Fe-regulated metal transporters IRT1 and IRT2 are expressed at low level to prevent high uptake of Zn through these metal transporters that might be in part responsible for Zn tolerance.