Cadmium and iron transport by members of a plant metal transporter family in Arabidopsis with homology to Nramp genes
Cadmium and iron transport by members of a plant metal transporter family in Arabidopsis with homology to Nramp genes
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DOI：
10.1073/pnas.97.9.4991
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发表时间：
2000-04-25
影响因子：
11.1
通讯作者：
Schroeder, JI
中科院分区：
文献类型：
--
作者：
Thomine, S;Wang, RC;Schroeder, JI
金属离子的体内平衡对于植物营养和抵抗有毒重金属是必不可少的。许多植物金属转运蛋白仍有待在分子水平上鉴定。在本研究中，我们已经从拟南芥中分离出AtNramp cDNA，并表明这些基因补充了金属吸收缺陷型酵母菌株smf1的表型。AtNramp与细菌、酵母、植物和动物中的Nramp基因家族具有同源性。AtNramp cDNA的表达增加了酵母对Cd 2+的敏感性和Cd 2+的积累。此外，AtNramp3和AtNramp4补充了酵母中的铁摄取突变体。这表明可能的作用，在植物中的铁运输，并揭示了异质性的Nramp转运蛋白的功能特性。在拟南芥中，AtNramp在金属充足的条件下在根和地上部分中表达。有趣的是，AtNramp3和AtNramp4由铁饥饿诱导。AtNramp3基因的破坏导致根系生长的镉抗性略有增强。此外，AtNramp3的过表达导致拟南芥根生长的镉敏感性和增加的铁积累，对Cd2+处理。我们的研究结果表明，植物中的Nramp基因编码金属转运蛋白和AtNramp运输的金属营养铁和有毒金属镉。
Metal cation homeostasis is essential for plant nutrition and resistance to toxic: heavy metals. Many plant metal transporters remain to be identified at the molecular level. In the present study, we have isolated AtNramp cDNAs from Arabidopsis and show that these genes complement the phenotype of a metal uptake deficient yeast strain, smf1. AtNramps show homology to the Nramp gene family in bacteria, yeast, plants, and animals. Expression of AtNramp cDNAs increases Cd2+ sensitivity and Cd2+ accumulation in yeast. Furthermore, AtNramp3 and AtNramp4 complement an iron uptake mutant in yeast. This suggests possible roles in iron transport in plants and reveals heterogeneity in the functional properties of Nramp transporters. In Arabidopsis, AtNramps are expressed in both roots and aerial parts under metal replete conditions. Interestingly, AtNramp3 and AtNramp4 are induced by iron starvation. Disruption of the AtNramp3 gene leads to slightly enhanced cadmium resistance of root growth. Furthermore, overexpression of AtNramp3 results in cadmium hypersensitivity of Arabidopsis root growth and increased accumulation of Fe, on Cd2+ treatment. Our results show that Nramp genes in plants encode metal transporters and that AtNramps transport both the metal nutrient Fe and the toxic metal cadmium.