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Planta

, Volume 229, Issue 6, pp 1171–1179 | Cite as

Arabidopsis IRT2 cooperates with the high-affinity iron uptake system to maintain iron homeostasis in root epidermal cells

  • Grégory Vert
  • Marie Barberon
  • Enric Zelazny
  • Mathilde Séguéla
  • Jean-François Briat
  • Catherine CurieEmail author
Original Article

Abstract

Iron is an essential nutrient for all organisms but toxic when present in excess. Consequently, plants carefully regulate their iron uptake, dependent on the FRO2 ferric reductase and the IRT1 transporter, to control its homeostasis. Arabidopsis IRT2 gene, whose expression is induced in root epidermis upon iron deprivation, was shown to encode a functional iron/zinc transporter in yeast, and proposed to function in iron acquisition from the soil. In this study, we demonstrate that, unlike its close homolog IRT1, IRT2 is not involved in iron absorption from the soil since overexpression of IRT2 does not rescue the iron uptake defect of irt1-1 mutant and since a null irt2 mutant shows no chlorosis in low iron. Consistently, an IRT2-green fluorescent fusion protein, transiently expressed in culture cells, localizes to intracellular vesicles. However, IRT2 appears strictly co-regulated with FRO2 and IRT1, supporting the view that IRT2 is an integral component of the root response to iron deficiency in root epidermal cells. We propose a model where IRT2 likely prevents toxicity from IRT1-dependent iron fluxes in epidermal cells, through compartmentalization.

Keywords

Arabidopsis IRT2 Iron uptake Metal Transport Root 

Notes

Acknowledgments

The authors are grateful to O. Bruguier (ISTEEM, University of Montpellier, France) for assistance in ICP-MS analyses. Work was supported by a B.D.I. fellowship awarded by the Centre National de la Recherche Scientifique (G.V) and by a thesis fellowship from the French Ministry of National Education, Research and Technology (M.B., M.S). Research was supported in part by an ACI (2000-51) from MENRT.

References

  1. Arrivault S, Senger T, Kramer U (2006) The Arabidopsis metal tolerance protein AtMTP3 maintains metal homeostasis by mediating Zn exclusion from the shoot under Fe deficiency and Zn oversupply. Plant J 46:861–879PubMedCrossRefGoogle Scholar
  2. Axelos M, Curie C, Mazzolini L, Bardet C, Lescure B (1992) A protocol for transient expression in Arabidopsis thaliana protoplasts isolated from cell suspension culture. Plant Physiol Biochem 30:123–128Google Scholar
  3. Becker D (1990) Binary vectors which allow the exchange of plant selectable markers and reporter genes. Nucleic Acids Res 18:203PubMedCrossRefGoogle Scholar
  4. Bienfait HF, Briel W, Mesland-Mul NT (1985) Free space iron pools in roots: generation and mobilization. Plant Physiol 78:596–600PubMedCrossRefGoogle Scholar
  5. Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J 16:735–743PubMedCrossRefGoogle Scholar
  6. Colangelo EP, Guerinot ML (2004) The essential basic helix-loop-helix protein FIT1 is required for the iron deficiency response. Plant Cell 16:3400–3412PubMedCrossRefGoogle Scholar
  7. Connolly EL, Campbell NH, Grotz N, Prichard CL, Guerinot ML (2003) Overexpression of the FRO2 ferric chelate reductase confers tolerance to growth on low iron and uncovers posttranscriptional control. Plant Physiol 133:1102–1110PubMedCrossRefGoogle Scholar
  8. Curie C, Briat JF (2003) Iron transport and signaling in plants. Annu Rev Plant Biol 54:183–206PubMedCrossRefGoogle Scholar
  9. Curie C, Panaviene Z, Loulergue C, Dellaporta SL, Briat JF, Walker EL (2001) Maize yellow stripe1 encodes a membrane protein directly involved in Fe(III) uptake. Nature 409:346–349PubMedCrossRefGoogle Scholar
  10. Dufner-Beattie J, Kuo YM, Gitschier J, Andrews GK (2004) The adaptive response to dietary zinc in mice involves the differential cellular localization and zinc regulation of the zinc transporters ZIP4 and ZIP5. J Biol Chem 279:49082–49090PubMedCrossRefGoogle Scholar
  11. Eide D, Broderius M, Fett J, Guerinot ML (1996) A novel iron-regulated metal transporter from plants identified by functional expression in yeast. Proc Natl Acad Sci USA 93:5624–5628PubMedCrossRefGoogle Scholar
  12. Emanuelsson O, Nielsen H, Brunak S, von Heijne G (2000) Predicting subcellular localization of proteins based on their N-terminal amino acid sequence. J Mol Biol 300:1005–1016PubMedCrossRefGoogle Scholar
  13. Henriques R, Jasik J, Klein M, Martinoia E, Feller U, Schell J, Pais MS, Koncz C (2002) Knock-out of Arabidopsis metal transporter gene IRT1 results in iron deficiency accompanied by cell differentiation defects. Plant Mol Biol 50:587–597PubMedCrossRefGoogle Scholar
  14. Huang L, Kirschke CP, Zhang Y, Yu YY (2005) The ZIP7 gene (Slc39a7) encodes a zinc transporter involved in zinc homeostasis of the Golgi apparatus. J Biol Chem 280:15456–15463PubMedCrossRefGoogle Scholar
  15. Jakoby M, Wang HY, Reidt W, Weisshaar B, Bauer P (2004) FRU (BHLH029) is required for induction of iron mobilization genes in Arabidopsis thaliana. FEBS Lett 577:528–534PubMedCrossRefGoogle Scholar
  16. Korshunova YO, Eide D, Clark WG, Guerinot ML, Pakrasi HB (1999) The IRT1 protein from Arabidopsis thaliana is a metal transporter with a broad substrate range. Plant Mol Biol 40:37–44PubMedCrossRefGoogle Scholar
  17. Kumanovics A, Poruk KE, Osborn KA, Ward DM, Kaplan J (2006) YKE4 (YIL023C) encodes a bidirectional zinc transporter in the endoplasmic reticulum of Saccharomyces cerevisiae. J Biol Chem 281:22566–22574PubMedCrossRefGoogle Scholar
  18. Lanquar V, Lelievre F, Bolte S, Hames C, Alcon C, Neumann D, Vansuyt G, Curie C, Schroder A, Kramer U, Barbier-Brygoo H, Thomine S (2005) Mobilization of vacuolar iron by AtNRAMP3 and AtNRAMP4 is essential for seed germination on low iron. EMBO J 24:4041–4051PubMedCrossRefGoogle Scholar
  19. Lobreaux S, Briat JF (1991) Ferritin accumulation and degradation in different organs of pea (Pisum sativum) during development. Biochem J 274:601–606PubMedGoogle Scholar
  20. MacDiarmid CW, Milanick MA, Eide DJ (2003) Induction of the ZRC1 metal tolerance gene in zinc-limited yeast confers resistance to zinc shock. J Biol Chem 278(17):15065–15072Google Scholar
  21. Nakai K, Kanehisa M (1992) A knowledge base for predicting protein localization sites in eukaryotic cells. Genomics 14:897–911PubMedCrossRefGoogle Scholar
  22. Palmgren MG (2001) Plant plasma membrane H+-ATPases: powerhouses for nutrient uptake. Annu Rev Plant Physiol Plant Mol Biol 52:817–845PubMedCrossRefGoogle Scholar
  23. Robinson NJ, Procter CM, Connolly EL, Guerinot ML (1999) A ferric-chelate reductase for iron uptake from soils. Nature 397:694–697PubMedCrossRefGoogle Scholar
  24. Schikora A, Thimm O, Linke B, Buckhout TJ, Müller M, Schmidt W (2006) Expression, localization, and regulation of the iron transporter LeIRT1 in tomato roots. Planta 284:101–108Google Scholar
  25. Schirawski J, Planchais S, Haenni AL (2000) An improved protocol for the preparation of protoplasts from an established Arabidopsis thaliana cell suspension culture and infection with RNA of turnip yellow mosaic tymovirus: a simple and reliable method. J Virol Methods 86:85–94PubMedCrossRefGoogle Scholar
  26. Seguela M, Briat JF, Vert G, Curie C (2008) Cytokinins negatively regulate the root iron uptake machinery in Arabidopsis through a growth-dependent pathway. Plant J 55:289–300PubMedCrossRefGoogle Scholar
  27. Thomine S, Lelievre F, Debarbieux E, Schroeder JI, Barbier-Brygoo H (2003) AtNRAMP3, a multispecific vacuolar metal transporter involved in plant responses to iron deficiency. Plant J 34:685–695PubMedCrossRefGoogle Scholar
  28. Varotto C, Maiwald D, Pesaresi P, Jahns P, Salamini F, Leister D (2002) The metal ion transporter IRT1 is necessary for iron homeostasis and efficient photosynthesis in Arabidopsis thaliana. Plant J 31:589–599PubMedCrossRefGoogle Scholar
  29. Vert G, Briat JF, Curie C (2001) Arabidopsis IRT2 gene encodes a root-periphery iron transporter. Plant J 26:181–189PubMedCrossRefGoogle Scholar
  30. Vert G, Grotz N, Dedaldechamp F, Gaymard F, Guerinot ML, Briat JF, Curie C (2002) IRT1, an Arabidopsis transporter essential for iron uptake from the soil and for plant growth. Plant Cell 14:1223–1233PubMedCrossRefGoogle Scholar
  31. Vert GA, Briat JF, Curie C (2003) Dual regulation of the Arabidopsis high-affinity root iron uptake system by local and long-distance signals. Plant Physiol 132:796–804PubMedCrossRefGoogle Scholar
  32. Yuan Y, Wu H, Wang N, Li J, Zhao W, Du J, Wang D, Ling HQ (2008) FIT interacts with AtbHLH38 and AtbHLH39 in regulating iron uptake gene expression for iron homeostasis in Arabidopsis. Cell Res 18:385–397PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Grégory Vert
    • 1
  • Marie Barberon
    • 1
  • Enric Zelazny
    • 1
  • Mathilde Séguéla
    • 1
  • Jean-François Briat
    • 1
  • Catherine Curie
    • 1
    Email author
  1. 1.Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des PlantesCNRS UMR 5004Montpellier Cedex 1France

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