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Further characterization of ferric-phytosiderophore transporters ZmYS1 and HvYS1 in maize and barley.

Ueno D, Yamaji N, Ma JF - J. Exp. Bot. (2009)

Bottom Line: Here, this transporter in maize (ZmYS1) and barley (HvYS1) was further characterized and compared in terms of expression pattern, diurnal change, and tissue-type specificity of localization.In contrast, ZmYS1 did not show such a rhythm in expression.These differences in gene expression pattern and tissue-type specificity of localization suggest that HvYS1 is only involved in primary Fe acquisition by barley roots, whereas ZmYS1 is involved in both primary Fe acquisition and intracellular transport of iron and other metals in maize.

View Article: PubMed Central - PubMed

Affiliation: Research Institute for Bioresources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.

ABSTRACT
Roots of some gramineous plants secrete phytosiderophores in response to iron deficiency and take up Fe as a ferric-phytosiderophore complex through the transporter YS1 (Yellow Stripe 1). Here, this transporter in maize (ZmYS1) and barley (HvYS1) was further characterized and compared in terms of expression pattern, diurnal change, and tissue-type specificity of localization. The expression of HvYS1 was specifically induced by Fe deficiency only in barley roots, and increased with the progress of Fe deficiency, whereas ZmYS1 was expressed in maize in the leaf blades and sheaths, crown, and seminal roots, but not in the hypocotyl. HvYS1 expression was not induced by any other metal deficiency. Furthermore, in maize leaf blades, the expression was higher in the young leaf blades showing severe chlorosis than in the old leaf blades showing no chlorosis. The expression of HvYS1 showed a distinct diurnal rhythm, reaching a maximum before the onset of phytosiderophore secretion. In contrast, ZmYS1 did not show such a rhythm in expression. Immunostaining showed that ZmYS1 was localized in the epidermal cells of both crown and lateral roots, with a polar localization at the distal side of the epidermal cells. In maize leaves, ZmYS1 was localized in mesophyll cells, but not epidermal cells. These differences in gene expression pattern and tissue-type specificity of localization suggest that HvYS1 is only involved in primary Fe acquisition by barley roots, whereas ZmYS1 is involved in both primary Fe acquisition and intracellular transport of iron and other metals in maize.

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Localization of ZmYS1 in maize leaf blade. A leaf blade of plants grown in Fe-sufficient (A) or Fe-deficient conditions with chlorosis (B) was used for immunostaining. The asterisk and arrow indicate autofluorescence of the chloroplast and ZmYS1 localization at the plasma membrane of the mesophyll cell, respectively. Scale bars indicate 100 μm.
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fig8: Localization of ZmYS1 in maize leaf blade. A leaf blade of plants grown in Fe-sufficient (A) or Fe-deficient conditions with chlorosis (B) was used for immunostaining. The asterisk and arrow indicate autofluorescence of the chloroplast and ZmYS1 localization at the plasma membrane of the mesophyll cell, respectively. Scale bars indicate 100 μm.

Mentions: In the leaf blade, ZmYS1 was not localized in the epidermal cells, but was detected on the peripheries of all mesophyll cells (Fig. 8). Heterologous studies in yeast and Xenopus oocytes have shown that ZmYS1 transports not only the Fe(III)–phytosiderophore complex, but also zinc–, copper–, and nickel–phytosiderophore complexes, and nickel, Fe(II), and Fe(III) complexes with NA (Roberts et al., 2004; Schaaf et al., 2004). The localization of ZmYS1 in the leaf blade suggests that ZmYS1 is also involved in the intracellular transport of these metals. However, since the expression of ZmYS1 in both roots and shoots only responded to Fe deficiency, but not to Cu and Zn deficiency at both the mRNA and protein levels (Roberts et al., 2004), it would be interesting in the future to examine whether ZmYS1 is also involved in intracellular transport of Zn and Cu in planta.


Further characterization of ferric-phytosiderophore transporters ZmYS1 and HvYS1 in maize and barley.

Ueno D, Yamaji N, Ma JF - J. Exp. Bot. (2009)

Localization of ZmYS1 in maize leaf blade. A leaf blade of plants grown in Fe-sufficient (A) or Fe-deficient conditions with chlorosis (B) was used for immunostaining. The asterisk and arrow indicate autofluorescence of the chloroplast and ZmYS1 localization at the plasma membrane of the mesophyll cell, respectively. Scale bars indicate 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2724700&req=5

fig8: Localization of ZmYS1 in maize leaf blade. A leaf blade of plants grown in Fe-sufficient (A) or Fe-deficient conditions with chlorosis (B) was used for immunostaining. The asterisk and arrow indicate autofluorescence of the chloroplast and ZmYS1 localization at the plasma membrane of the mesophyll cell, respectively. Scale bars indicate 100 μm.
Mentions: In the leaf blade, ZmYS1 was not localized in the epidermal cells, but was detected on the peripheries of all mesophyll cells (Fig. 8). Heterologous studies in yeast and Xenopus oocytes have shown that ZmYS1 transports not only the Fe(III)–phytosiderophore complex, but also zinc–, copper–, and nickel–phytosiderophore complexes, and nickel, Fe(II), and Fe(III) complexes with NA (Roberts et al., 2004; Schaaf et al., 2004). The localization of ZmYS1 in the leaf blade suggests that ZmYS1 is also involved in the intracellular transport of these metals. However, since the expression of ZmYS1 in both roots and shoots only responded to Fe deficiency, but not to Cu and Zn deficiency at both the mRNA and protein levels (Roberts et al., 2004), it would be interesting in the future to examine whether ZmYS1 is also involved in intracellular transport of Zn and Cu in planta.

Bottom Line: Here, this transporter in maize (ZmYS1) and barley (HvYS1) was further characterized and compared in terms of expression pattern, diurnal change, and tissue-type specificity of localization.In contrast, ZmYS1 did not show such a rhythm in expression.These differences in gene expression pattern and tissue-type specificity of localization suggest that HvYS1 is only involved in primary Fe acquisition by barley roots, whereas ZmYS1 is involved in both primary Fe acquisition and intracellular transport of iron and other metals in maize.

View Article: PubMed Central - PubMed

Affiliation: Research Institute for Bioresources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.

ABSTRACT
Roots of some gramineous plants secrete phytosiderophores in response to iron deficiency and take up Fe as a ferric-phytosiderophore complex through the transporter YS1 (Yellow Stripe 1). Here, this transporter in maize (ZmYS1) and barley (HvYS1) was further characterized and compared in terms of expression pattern, diurnal change, and tissue-type specificity of localization. The expression of HvYS1 was specifically induced by Fe deficiency only in barley roots, and increased with the progress of Fe deficiency, whereas ZmYS1 was expressed in maize in the leaf blades and sheaths, crown, and seminal roots, but not in the hypocotyl. HvYS1 expression was not induced by any other metal deficiency. Furthermore, in maize leaf blades, the expression was higher in the young leaf blades showing severe chlorosis than in the old leaf blades showing no chlorosis. The expression of HvYS1 showed a distinct diurnal rhythm, reaching a maximum before the onset of phytosiderophore secretion. In contrast, ZmYS1 did not show such a rhythm in expression. Immunostaining showed that ZmYS1 was localized in the epidermal cells of both crown and lateral roots, with a polar localization at the distal side of the epidermal cells. In maize leaves, ZmYS1 was localized in mesophyll cells, but not epidermal cells. These differences in gene expression pattern and tissue-type specificity of localization suggest that HvYS1 is only involved in primary Fe acquisition by barley roots, whereas ZmYS1 is involved in both primary Fe acquisition and intracellular transport of iron and other metals in maize.

Show MeSH
Related in: MedlinePlus