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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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Effect of Fe status on the expression level of ZmYS1 in different leaf blades. Maize seedlings were grown in a nutrient solution with Fe for 7 d and then in a solution without Fe for 4 d. (A) A maize plant showing Fe deficiency symptoms in the young leaves. (B) SPAD value of different leaf blades with or without Fe supply. (C) Expression of ZmYS1 in different leaf blades. The expression level of ZmYS1 in different tissues was determined by quantitative RT-PCR. The mRNA levels are relative to those of the +Fe plants. Different letters indicate a significant difference at P <0.05. Data are means ±SD (n=3).
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fig3: Effect of Fe status on the expression level of ZmYS1 in different leaf blades. Maize seedlings were grown in a nutrient solution with Fe for 7 d and then in a solution without Fe for 4 d. (A) A maize plant showing Fe deficiency symptoms in the young leaves. (B) SPAD value of different leaf blades with or without Fe supply. (C) Expression of ZmYS1 in different leaf blades. The expression level of ZmYS1 in different tissues was determined by quantitative RT-PCR. The mRNA levels are relative to those of the +Fe plants. Different letters indicate a significant difference at P <0.05. Data are means ±SD (n=3).

Mentions: The expression of ZmYS1 was then further examined in different leaf blades with different Fe status. To generate leaf blades with different Fe status, maize seedlings were first grown in a nutrient solution containing Fe and then transferred to a solution without Fe. After 4 d in the –Fe solution, the younger leaves showed Fe deficiency symptoms of chlorosis, while the older leaves stayed green (Fig. 3A). The SPAD value of the youngest leaf without Fe supply was only half of that in plants with continuous Fe supply (P <0.01; Fig. 3B), whereas the oldest leaf had similar SPAD values in the +Fe- and –Fe-treated plants (P >0.05). Notably, the expression level of ZmYS1 tended to increase with decreasing SPAD value in leaf blades, with >20-fold difference between the youngest and the oldest leaf blade (P <0.01; Fig. 3C). These results indicate that the expression of ZmYS1 is regulated by Fe status in leaf blades.


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

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

Effect of Fe status on the expression level of ZmYS1 in different leaf blades. Maize seedlings were grown in a nutrient solution with Fe for 7 d and then in a solution without Fe for 4 d. (A) A maize plant showing Fe deficiency symptoms in the young leaves. (B) SPAD value of different leaf blades with or without Fe supply. (C) Expression of ZmYS1 in different leaf blades. The expression level of ZmYS1 in different tissues was determined by quantitative RT-PCR. The mRNA levels are relative to those of the +Fe plants. Different letters indicate a significant difference at P <0.05. Data are means ±SD (n=3).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig3: Effect of Fe status on the expression level of ZmYS1 in different leaf blades. Maize seedlings were grown in a nutrient solution with Fe for 7 d and then in a solution without Fe for 4 d. (A) A maize plant showing Fe deficiency symptoms in the young leaves. (B) SPAD value of different leaf blades with or without Fe supply. (C) Expression of ZmYS1 in different leaf blades. The expression level of ZmYS1 in different tissues was determined by quantitative RT-PCR. The mRNA levels are relative to those of the +Fe plants. Different letters indicate a significant difference at P <0.05. Data are means ±SD (n=3).
Mentions: The expression of ZmYS1 was then further examined in different leaf blades with different Fe status. To generate leaf blades with different Fe status, maize seedlings were first grown in a nutrient solution containing Fe and then transferred to a solution without Fe. After 4 d in the –Fe solution, the younger leaves showed Fe deficiency symptoms of chlorosis, while the older leaves stayed green (Fig. 3A). The SPAD value of the youngest leaf without Fe supply was only half of that in plants with continuous Fe supply (P <0.01; Fig. 3B), whereas the oldest leaf had similar SPAD values in the +Fe- and –Fe-treated plants (P >0.05). Notably, the expression level of ZmYS1 tended to increase with decreasing SPAD value in leaf blades, with >20-fold difference between the youngest and the oldest leaf blade (P <0.01; Fig. 3C). These results indicate that the expression of ZmYS1 is regulated by Fe status in leaf blades.

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