Characterization of the high affinity Zn transporter from Noccaea caerulescens, NcZNT1, and dissection of its promoter for its role in Zn uptake and hyperaccumulation
Characterization of the high affinity Zn transporter from Noccaea caerulescens, NcZNT1, and dissection of its promoter for its role in Zn uptake and hyperaccumulation
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DOI：
10.1111/j.1469-8137.2012.04144.x
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发表时间：
2012-07-01
期刊：
影响因子：
9.4
通讯作者：
Kochian, Leon V.
中科院分区：
文献类型：
--
作者：
Milner, Matthew J.;Craft, Eric;Kochian, Leon V.
在本文中，我们进行了详细的分析，ZIP家族转运蛋白，NcZNT 1，在锌（Zn）/镉（Cd）超积累植物物种，蓝桉，以前被称为Thlaspi caerulescens。NcZNT 1被认为是初级根Zn/Cd吸收转运蛋白。NcZNT 1在植物和异源系统中的运输功能的表征，以及NcZNT 1基因表达和NcZNT 1蛋白定位的分析进行。我们发现，NcZNT 1不仅在根表皮中表达，而且在根和茎的脉管系统中高度表达，这表明在长距离金属运输中的作用。此外，NcZNT 1被发现是一个质膜转运蛋白，介导锌，但不是镉，铁（Fe），锰（Mn）或铜（Cu）吸收到植物细胞。NcZNT 1启动子的两个新区域被鉴定，这可能涉及NcZNT 1的过表达及其受植物锌状态调节的能力。总之，我们在这里证明，NcZNT 1发挥作用，锌，而不是镉从土壤中的吸收，并根据其强表达在根和芽的脉管系统，可以参与长距离运输锌从根到地上部通过木质部。
In this paper, we conducted a detailed analysis of the ZIP family transporter, NcZNT1, in the zinc (Zn)/cadmium (Cd) hyperaccumulating plant species, Noccaea caerulescens, formerly known as Thlaspi caerulescens. NcZNT1 was previously suggested to be the primary root Zn/Cd uptake transporter. Both a characterization of NcZNT1 transport function in planta and in heterologous systems, and an analysis of NcZNT1 gene expression and NcZNT1 protein localization were carried out. We show that NcZNT1 is not only expressed in the root epidermis, but also is highly expressed in the root and shoot vasculature, suggesting a role in long-distance metal transport. Also, NcZNT1 was found to be a plasma membrane transporter that mediates Zn but not Cd, iron (Fe), manganese (Mn) or copper (Cu) uptake into plant cells. Two novel regions of the NcZNT1 promoter were identified which may be involved in both the hyperexpression of NcZNT1 and its ability to be regulated by plant Zn status. In conclusion, we demonstrate here that NcZNT1 plays a role in Zn and not Cd uptake from the soil, and based on its strong expression in the root and shoot vasculature, could be involved in long-distance transport of Zn from the root to the shoot via the xylem.