The Crotalaria juncea metal transporter CjNRAMP1 has a high Fe uptake activity, even in an environment with high Cd contamination
The Crotalaria juncea metal transporter CjNRAMP1 has a high Fe uptake activity, even in an environment with high Cd contamination
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DOI：
10.1080/15226514.2018.1501333
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发表时间：
2018-12
影响因子：
3.7
通讯作者：
Tsugumi Nakanishi-Masuno;N. Shitan;A. Sugiyama;Kojiro Takanashi;S. Inaba;S. Kaneko;K. Yazaki
中科院分区：
文献类型：
--
作者：
Tsugumi Nakanishi-Masuno;N. Shitan;A. Sugiyama;Kojiro Takanashi;S. Inaba;S. Kaneko;K. Yazaki
摘要 富含金属的豆科植物猪屎豆的叶子中积累了大量的铁和镉。金属转运蛋白 NRAMP 家族的一个成员是从芥菜中克隆出来的。该克隆的氨基酸序列被命名为 CjNRAMP1，与拟南芥 AtNRAMP1 的序列相似，后者参与 Fe 和 Cd 转运。器官特异性分析表明，CjNRAMP1 mRNA 主要在芥菜植物的叶子、茎和根中表达。使用与 CjNRAMP1 融合的绿色荧光蛋白表明其定位于植物细胞的质膜。使用金属转运系统受损的酵母菌株进行的互补实验表明，CjNRAMP1 在细胞内向内方向转运 Fe 和 Cd。过表达 CjNRAMP1 的转基因拟南芥植物表现出对 Cd 的高耐受性，转基因植物中 Cd 从根到叶的易位明显高于野生型植物。 CjNRAMP1 的过表达导致地上部和根中 Fe 的积累量增加，表明 CjNRAMP1 将 Fe 和 Cd 识别为底物，并且 CjNRAMP1 的高 Cd 耐受性是由于其强大的 Fe 吸收活性，即使在根际存在高 Cd 浓度的情况下也是如此。
Abstract Large quantities of Fe and Cd accumulate in the leaves of the metal-accumulating leguminous plant, Crotalaria juncea. A member of the metal transporter NRAMP family was cloned from C. juncea. The amino acid sequence of this clone, designated CjNRAMP1, was similar to the sequence of Arabidopsis AtNRAMP1, which is involved in Fe and Cd transport. Organ-specific analysis showed that CjNRAMP1 mRNA was expressed mainly in the leaves of C. juncea plants, as well as in stems and roots. Use of green fluorescent protein fused to CjNRAMP1 suggested its localization to the plasma membranes of plant cells. Complementation experiments using yeast strains with impaired metal transport systems showed that CjNRAMP1 transported both Fe and Cd in an inward direction within the cells. Transgenic Arabidopsis plants overexpressing CjNRAMP1 showed high tolerance to Cd, with Cd translocation from roots to leaves being substantially greater in transgenic than in wild-type plants. Overexpression of CjNRAMP1 resulted in a greater accumulation of Fe in shoots and roots, suggesting that CjNRAMP1 recognizes Fe and Cd as substrates and that the high Cd tolerance of CjNRAMP1 is due to its strong Fe uptake activity, even in the presence of high Cd concentrations in the rhizosphere.