AtIRT1, the Primary Iron Uptake Transporter in the Root, Mediates Excess Nickel Accumulation in Arabidopsis thaliana

Nickel (Ni) is an essential nutrient for plants, but excessive amounts can be toxic. Ni competes with iron (Fe) in vivo, raising the possibility that Ni is competitively taken up via the Fe uptake system in plants. Here, we show evidence that AtIRT1, the primary Fe2+ uptake transporter in the root,...

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Veröffentlicht in:Plant and cell physiology 2011-08, Vol.52 (8), p.1433-1442
Hauptverfasser: Nishida, Sho, Tsuzuki, Chisato, Kato, Aki, Aisu, Ayaka, Yoshida, Junko, Mizuno, Takafumi
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Sprache:eng
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Zusammenfassung:Nickel (Ni) is an essential nutrient for plants, but excessive amounts can be toxic. Ni competes with iron (Fe) in vivo, raising the possibility that Ni is competitively taken up via the Fe uptake system in plants. Here, we show evidence that AtIRT1, the primary Fe2+ uptake transporter in the root, mediates Ni accumulation in Arabidopsis thaliana. In hydroponic cultures, excess Ni exposure increased Fe accumulation and the relative transcription level of AtIRT1 in roots, indicating that excess Ni induces AtIRT1 expression in roots. An Fe-deficient treatment increased Ni accumulation in plants, suggesting that excess Ni was absorbed via the Fe uptake system, which was induced by Fe starvation. Moreover, Ni accumulation under Fe-deficient conditions was markedly lower in AtIRT1-defective mutants than in the wild-type, Col-0. Furthermore, AtIRT1 showed Ni2+ uptake activity in a yeast expression system. These data demonstrate that AtIRT1 transports Ni2+ in roots, and strongly suggest that Ni accumulation is further accelerated by AtIRT1 that is expressed in response to excess Ni.
ISSN:0032-0781
1471-9053
DOI:10.1093/pcp/pcr089