Expression of cadR Enhances its Specific Activity for Cd Detoxification and Accumulation in Arabidopsis
Expression of cadR Enhances its Specific Activity for Cd Detoxification and Accumulation in Arabidopsis
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拟南芥中cadR的表达增强其Cd解毒和积累的比活性
DOI：
10.1093/pcp/pcw093
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发表时间：
2016-08-01
影响因子：
4.9
通讯作者：
Zhang, Haiyan
中科院分区：
文献类型：
--
作者：
Li, Jingrui;Wei, Xuezhi;Zhang, Haiyan
镉（Cd）是一种过渡金属，在生物系统中具有高毒性。人为排放的镉增加了地球化学循环和镉在生物圈中的数量。在这里，我们研究了实用的细菌镉结合蛋白，CadR，镉污染的修复。利用花椰菜花叶病毒（CaMV）35 S启动子、叶绿素a/b结合蛋白2基因（CAB 2）启动子和Rubisco复合物小亚基（RbcS）转运肽成功地将CadR定位于叶绿体。在短期（2天）暴露于镉，cadR转基因植物表现出高达2.9倍的镉积累在根相比，未转化的植物。在中期（7 d）Cd胁迫下，叶片中Cd含量开始增加，但野生型和转cadR基因植株之间没有差异。在长期（16 d）暴露于Cd的条件下，转cadR基因植株叶片中Cd的积累量大于未转基因植株。总镉积累（mg/株）在芽和根的植物表达cadR显着高于（高达3.5倍，在芽和5.2倍，根）比那些未转化的植物。我们还发现，将CadR靶向叶绿体促进叶绿体金属稳态和Chl B积累。我们的研究结果表明，操纵叶绿体或细胞质中的螯合能力可能是有效的修改积累和抗性镉。
Cadmium (Cd) is a transition metal that is highly toxic in biological systems. Anthropogenic emissions of Cd have increased biogeochemical cycling and the amount of Cd in the biosphere. Here we studied the utility of a bacterial Cd-binding protein, CadR, for the remediation of Cd contamination. CadR was successfully targeted to chloroplasts using a constitutive Cauliflower mosaic virus (CaMV) 35S promoter or a shoot-specific Chl a/b-binding protein 2 gene (CAB2) promoter and an RbcS (small subunit of the Rubisco complex) transit peptide. Under short-term (2 d) exposure to Cd, the cadR transgenic plants showed up to a 2.9-fold Cd accumulation in roots compared with untransformed plants. Under medium term (7 d) exposure to Cd, the concentrations of Cd in leaves began to increase but there were no differences between the wild type and the cadR transgenic plants. Under long-term (16 d) exposure to Cd, the cadR transgenic plants accumulated greater amounts of Cd in leaves than the untransformed plants. Total Cd accumulation (mg per plant) in shoots and roots of the plants expressing cadR were significantly higher (up to 3.5-fold in shoots and 5.2-fold in roots) than those of the untransformed plants. We also found that targeting CadR to chloroplasts facilitated chloroplastic metal homeostasis and Chl b accumulation. Our results demonstrate that manipulating chelating capacity in chloroplasts or in the cytoplasm may be effective in modifying both the accumulation of and resistance to Cd.