AtAMT1;4, a pollen-specific high-affinity ammonium transporter of the plasma membrane in Arabidopsis.
AtAMT1;4, a pollen-specific high-affinity ammonium transporter of the plasma membrane in Arabidopsis.
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DOI：
10.1093/pcp/pcn186
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发表时间：
2009-01
影响因子：
4.9
通讯作者：
von Wiren, Nicolaus
中科院分区：
文献类型：
--
作者：
Yuan, Lixing;Graff, Lucile;Loque, Dominique;Kojima, Soichi;Tsuchiya, Yumiko N.;Takahashi, Hideki;von Wiren, Nicolaus
花粉是花朵中重要的氮汇，可确保花粉活力。由于花粉细胞在成熟和发芽过程中是同质分离的，因此需要膜转运蛋白来跨花粉质膜输入氮。本研究描述了铵转运蛋白 AtAMT1;4 的特征，AtAMT1;4 是拟南芥 AMT1 家族中迄今为止未知的成员，被认为参与将铵转运到花粉中。当在酵母中异源表达或在拟南芥根中过度表达时，AtAMT1;4 基因编码功能性铵转运蛋白。对流入 AtAMT1;4 转化植物根部的 15N 标记铵进行浓度依赖性分析，将 AtAMT1;4 表征为 Km 为 17μM 的高亲和力转运蛋白。 RNA 和蛋白质凝胶印迹分析显示 AtAMT1;4 在花中表达，启动子基因与绿色荧光蛋白 (GFP) 的融合进一步确定了其在花粉粒和花粉管中的专有表达。 AtAMT1;4 蛋白似乎定位于质膜，如对质膜富集的膜组分的蛋白质凝胶印迹分析以及花粉粒和花粉管中 GFP 标记的 AtAMT1;4 蛋白的可视化所示。然而，在转座子标记品系中未观察到与花粉功能相关的表型，其中 AtAMT1;4 表达被破坏。这些结果表明AtAMT1;4介导穿过花粉质膜的铵吸收，通过铵吸收或回收来促进花粉的氮营养。
Pollen represents an important nitrogen sink in flowers to ensure pollen viability. Since pollen cells are symplasmically isolated during maturation and germination, membrane transporters are required for nitrogen import across the pollen plasma membrane. This study describes the characterization of the ammonium transporter AtAMT1;4, a so far uncharacterized member of the Arabidopsis AMT1 family, which is suggested to be involved in transporting ammonium into pollen. The AtAMT1;4 gene encodes a functional ammonium transporter when heterologously expressed in yeast or when overexpressed in Arabidopsis roots. Concentration-dependent analysis of 15N-labeled ammonium influx into roots of AtAMT1;4-transformed plants allowed characterization of AtAMT1;4 as a high-affinity transporter with a Km of 17 μM. RNA and protein gel blot analysis showed expression of AtAMT1;4 in flowers, and promoter–gene fusions to the green fluorescent protein (GFP) further defined its exclusive expression in pollen grains and pollen tubes. The AtAMT1;4 protein appeared to be localized to the plasma membrane as indicated by protein gel blot analysis of plasma membrane-enriched membrane fractions and by visualization of GFP-tagged AtAMT1;4 protein in pollen grains and pollen tubes. However, no phenotype related to pollen function could be observed in a transposon-tagged line, in which AtAMT1;4 expression is disrupted. These results suggest that AtAMT1;4 mediates ammonium uptake across the plasma membrane of pollen to contribute to nitrogen nutrition of pollen via ammonium uptake or retrieval.
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影响因子：
3.4
作者：
Fernando, DD
通讯作者：
Fernando, DD
影响因子：
--
作者：
Foster, Justin;Lee, Yong-Hwa;Tegeder, Mechthild
通讯作者：
Tegeder, Mechthild
影响因子：
7.4
作者：
Kaiser, BN;Rawat, SR;Glass, ADM
通讯作者：
Glass, ADM
影响因子：
7.4
作者：
Pina, C;Pinto, F;Becker, JD
通讯作者：
Becker, JD
影响因子：
7.2
作者：
SAUER, N;STADLER, R
通讯作者：
STADLER, R