Root-selective expression of AtCAX4 and AtCAX2 results in reduced lamina cadmium in field-grown Nicotiana tabacum L.
Root-selective expression of AtCAX4 and AtCAX2 results in reduced lamina cadmium in field-grown Nicotiana tabacum L.
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DOI：
10.1111/j.1467-7652.2008.00390.x
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发表时间：
2009-04-01
影响因子：
13.8
通讯作者：
Wagner, George J.
中科院分区：
文献类型：
--
作者：
Korenkov, Victor;King, Brian;Wagner, George J.
为了评估增强根液泡镉（Cd）螯合对叶镉积累的影响，在低镉剂量下，通常发生在农业中，叶镉积累进行了研究，在田间生长的烟草植物表达基因编码的高容量镉，液泡膜定位，二价阳离子/H反向转运蛋白AtCAX 4和AtCAX 2（AtCAX，拟南芥阳离子交换）。以前已经表明，根液泡膜囊泡分离的植物表达这些基因，指导根选择性启动子，表现出增强的镉运输活性，和年轻的植物表现出增强的根镉积累时，生长在含有0.02 μ m的镉，中等镉剂量的溶液培养。在这篇文章中，我们提出的结果表明，表达AtCAX 2或AtCAX 4的成熟植物的下叶，在两种不同的根选择性启动子的控制下，积累15%-25%的叶片镉比对照植物生长在现场（3年，三种不同的收集方法）。相互嫁接实验AtCAX 2芽到对照根（反之亦然），生长在溶液培养0.005亩镉，表明根控制镉的转运和积累在地上部的控制和AtCAX 2和AtCAX 4烟草植物暴露于低浓度的镉。结果是一致的模型，在根细胞液泡膜中的Cd/H逆向转运蛋白活性的补充增强根镉螯合，导致减少镉的易位到地上部的田间生长的植物。这些结果表明，人类从食物和烟草的使用镉摄入量可以减少通过增强根液泡隔离这种污染物。
To assess the impact of enhanced root vacuole cadmium (Cd) sequestration on leaf Cd accumulation under a low Cd dose, as generally occurs in agriculture, leaf Cd accumulation was examined in field-grown tobacco plants expressing genes encoding the high-capacity-Cd, tonoplast-localized, divalent cation/H antiporters AtCAX4 and AtCAX2 (AtCAX, Arabidopsis cation exchanger). It has been shown previously that root tonoplast vesicles isolated from plants expressing these genes, directed by root-selective promoters, show enhanced Cd transport activity, and young plants show enhanced root Cd accumulation when grown in solution culture containing 0.02 mu m Cd, a moderate Cd dose. In this article, we present results which show that the lower leaves of mature plants expressing AtCAX2 or AtCAX4, under the control of two different root-selective promoters, accumulate 15%-25% less lamina Cd than control plants when grown in the field (3 years, three different collection methods). Reciprocal grafting experiments of AtCAX2 shoots onto control roots (and vice versa), grown in solution culture with 0.005 mu m Cd, indicated that the root controls Cd translocation and accumulation in the shoot in control and AtCAX2 and AtCAX4 tobacco plants exposed to low Cd concentration. The results are consistent with a model in which supplementation of Cd/H antiporter activity in root cell tonoplasts enhances root Cd sequestration, resulting in decreased translocation of Cd to the shoot of field-grown plants. These results suggest that human Cd intake from food and tobacco use could be reduced via the enhancement of root vacuolar sequestration of this pollutant.