Engineering metal-binding sites of bacterial CusF to enhance Zn/Cd accumulation and resistance by subcellular targeting.
Engineering metal-binding sites of bacterial CusF to enhance Zn/Cd accumulation and resistance by subcellular targeting.
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DOI：
10.1016/j.jhazmat.2015.09.054
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发表时间：
2016-01
影响因子：
13.6
通讯作者：
Pengli Yu;Jinhong Yuan;Hui Zhang;X. Deng;Mi Ma;Haiyan Zhang
中科院分区：
文献类型：
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作者：
Pengli Yu;Jinhong Yuan;Hui Zhang;X. Deng;Mi Ma;Haiyan Zhang
周质蛋白 CusF 作为金属伴侣介导大肠杆菌的铜抗性。 CusF 不含半胱氨酸残基，几乎不与二价阳离子结合。在这里，我们研究了 CusF 的半胱氨酸取代突变体（称为 mCusF）对锌/镉（Zn/Cd）积累和抗性的影响。我们将 mCusF 靶向拟南芥中的不同亚细胞区室。我们发现表达液泡靶向 mCusF 的植物比 WT 和具有细胞壁靶向或细胞质 mCusF 的植物更能抵抗过量的 Zn。在长期暴露于过量的锌的情况下，所有转基因株系在芽中积累的锌比未转化的植物多（高达2.3倍）。重要的是，具有细胞质 mCusF 的植物比具有靶向分泌途径的 mCusF 的植物表现出更高的 Zn 从根到芽的易位效率。此外，转基因品系表现出增强的镉抗性和根部到茎部镉易位的显着增加。我们还发现所有转基因植物在镉暴露下都大大改善了锰 (Mn) 和铁 (Fe) 的稳态。我们的结果表明，mCusF 的异源表达可用于设计一种新的 Zn/Cd 植物修复策略，我们的发现也加深了我们对通过适当的根/芽分配机制和 Mn 和 Fe 稳态积累来减轻植物中 Cd 毒性的机制基础的认识。
The periplasmic protein CusF acts as a metallochaperone to mediate Cu resistance inEscherichia coli. CusF does not contain cysteine residues and barely binds to divalent cations. Here, we addressed effects of cysteine-substitution mutant (named as mCusF) of CusF on zinc/cadmium (Zn/Cd) accumulation and resistance. We targeted mCusF to different subcellular compartments in Arabidopsis. We found that plants expressing vacuole-targeted mCusF were more resistant to excess Zn than WT and plants with cell wall-targeted or cytoplasmic mCusF. Under long-term exposure to excess Zn, all transgenic lines accumulated more Zn (up to 2.3-fold) in shoots than the untransformed plants. Importantly, plants with cytoplasmic mCusF showed higher efficiency of Zn translocation from root to shoot than plants with secretory pathway-targeted-mCusF. Furthermore, the transgenic lines exhibited enhanced resistance to Cd and significant increase in root-to-shoot Cd translocation. We also found all transgenic plants greatly improved manganese (Mn) and iron (Fe) homeostasis under Cd exposure. Our results demonstrate heterologous expression of mCusF could be used to engineer a new phytoremediation strategy for Zn/Cd and our finding also deepen our insights into mechanistic basis for relieving Cd toxicity in plants through proper root/shoot partitioning mechanism and homeostatic accumulation of Mn and Fe.