Schaaf, Gabriel ; Schikora, Adam ; Häberle, Jennifer ; Vert, Grégory ; Ludewig, Uwe ; Briat, Jean-François ; Curie, Catherine ; Wirén, Nicolaus von (2005)
A putative function for the arabidopsis Fe-Phytosiderophore transporter homolog AtYSL2 in Fe and Zn homeostasis.
In: Plant & cell physiology, 46 (5)
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Although Arabidopsis thaliana does not produce phytosiderophores (PS) under Fe deficiency, it contains eight homologs of the metal-PS/metal-nicotianamine (NA) transporter ZmYS1 from maize. This study aimed to investigate whether one of the closest Arabidopsis homologs to ZmYS1, AtYSL2, is involved in metal-chelate transport. Northern analysis revealed high expression levels of AtYSL2 in Fe-sufficient or Fe-resupplied roots, while under Fe deficiency transcript levels decreased. Quantitative real-time polymerase chain reaction (PCR) and analysis of transgenic plants expressing an AtYSL2 promoter::beta-glucuronidase gene further allowed the detection of down-regulated AtYSL2 gene expression under Zn and Fe deficiency. In contrast to ZmYS1, AtYSL2 did not mediate metal-PS or metal-NA transport in yeast mutants defective in Cu or Fe uptake, nor did AtYSL2 mediate Fe(II)-NA-, Fe(III)-NA- or Ni(II)-NA-inducible currents when assayed by two-electrode voltage clamp in Xenopus oocytes. Moreover, truncation of the N-terminus to remove putative phosphorylation sites that might trigger autoinhibition did not confer functionality to AtYSL2. A direct growth comparison of yeast cells transformed with AtYSL2 in two different yeast expression vectors showed that transformation with empty pFL61 repressed growth even under non-limiting Fe supply. We therefore conclude that the yeast complementation assay previously employed does not allow the identification of AtYSL2 as an Fe-NA transporter. Transgenic plants expressing an AtYSL2 promoter::beta-glucuronidase gene showed expression in root endodermis and pericycle cells facing the meta-xylem tubes. Taken together, our investigations support an involvement of AtYSL2 in Fe and Zn homeostasis, although functionality or substrate specificity are likely to differ between AtYSL2 and ZmYS1.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2005 |
| Autor(en): | Schaaf, Gabriel ; Schikora, Adam ; Häberle, Jennifer ; Vert, Grégory ; Ludewig, Uwe ; Briat, Jean-François ; Curie, Catherine ; Wirén, Nicolaus von |
| Art des Eintrags: | Bibliographie |
| Titel: | A putative function for the arabidopsis Fe-Phytosiderophore transporter homolog AtYSL2 in Fe and Zn homeostasis |
| Sprache: | Englisch |
| Publikationsjahr: | 2005 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Plant & cell physiology |
| Jahrgang/Volume einer Zeitschrift: | 46 |
| (Heft-)Nummer: | 5 |
| Kurzbeschreibung (Abstract): | Although Arabidopsis thaliana does not produce phytosiderophores (PS) under Fe deficiency, it contains eight homologs of the metal-PS/metal-nicotianamine (NA) transporter ZmYS1 from maize. This study aimed to investigate whether one of the closest Arabidopsis homologs to ZmYS1, AtYSL2, is involved in metal-chelate transport. Northern analysis revealed high expression levels of AtYSL2 in Fe-sufficient or Fe-resupplied roots, while under Fe deficiency transcript levels decreased. Quantitative real-time polymerase chain reaction (PCR) and analysis of transgenic plants expressing an AtYSL2 promoter::beta-glucuronidase gene further allowed the detection of down-regulated AtYSL2 gene expression under Zn and Fe deficiency. In contrast to ZmYS1, AtYSL2 did not mediate metal-PS or metal-NA transport in yeast mutants defective in Cu or Fe uptake, nor did AtYSL2 mediate Fe(II)-NA-, Fe(III)-NA- or Ni(II)-NA-inducible currents when assayed by two-electrode voltage clamp in Xenopus oocytes. Moreover, truncation of the N-terminus to remove putative phosphorylation sites that might trigger autoinhibition did not confer functionality to AtYSL2. A direct growth comparison of yeast cells transformed with AtYSL2 in two different yeast expression vectors showed that transformation with empty pFL61 repressed growth even under non-limiting Fe supply. We therefore conclude that the yeast complementation assay previously employed does not allow the identification of AtYSL2 as an Fe-NA transporter. Transgenic plants expressing an AtYSL2 promoter::beta-glucuronidase gene showed expression in root endodermis and pericycle cells facing the meta-xylem tubes. Taken together, our investigations support an involvement of AtYSL2 in Fe and Zn homeostasis, although functionality or substrate specificity are likely to differ between AtYSL2 and ZmYS1. |
| Fachbereich(e)/-gebiet(e): | 10 Fachbereich Biologie ?? fb10_botanik ?? 10 Fachbereich Biologie > Pflanzenernährung und Biomasse |
| Hinterlegungsdatum: | 16 Mär 2010 14:09 |
| Letzte Änderung: | 28 Feb 2022 12:40 |
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