Engineering expression of bacterial polyphosphate kinase in tobacco for mercury remediation
Engineering expression of bacterial polyphosphate kinase in tobacco for mercury remediation
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DOI：
10.1007/s00253-006-0336-3
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发表时间：
2006-10-01
影响因子：
5
通讯作者：
Pan-Hou, Hidemitsu
中科院分区：
文献类型：
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作者：
Nagata, Takeshi;Kiyono, Masako;Pan-Hou, Hidemitsu
为了开发植物从受污染的地方隔离和积累汞的潜力，我们在植物启动子的控制下，通过基因工程的方式表达了一个细菌PPK基因，编码多聚磷酸酶(PPK)。将含有PPK完整编码区的植物表达载体pPKT116用于农杆菌介导的烟草基因转移。获得了大量独立的转基因烟草植株，其中一些PPK基因稳定整合到植物基因组中，并在转基因烟草中大量翻译成预期的PPK蛋白。Hg2+的存在没有引起转基因烟草明显的形态异常，在含有正常毒性水平的Hg2+的培养基上，转基因烟草的生长、开花和结实与野生型烟草相似。与野生型烟草相比，转PPK基因烟草对Hg2+表现出更强的抗性，积累了更多的汞。这些结果表明，PPK特异的聚磷酸盐具有降低汞毒性的能力，可能是通过螯合机制，并在转基因烟草中积累汞。根据本研究的结果，PPK基因在转基因烟草植株中的表达可能为汞污染的植物修复提供一种手段。
To develop the potential of plants to sequester and accumulate mercurials from the contaminated sites, we engineered a tobacco (Nicotiana tabacum) plant to express a bacterial ppk gene, encoding polyphosphate kinase (PPK), under control of a plant promoter. The designated plant expression plasmid pPKT116 that contains the entire coding region of ppk was used for Agrobacterium-mediated gene transfer into tobacco plants. A large number of independent transgenic tobacco plants were obtained, in some of which the ppk gene was stably integrated in the plant genome and substantially translated to the expected PPK protein in the transgenic tobacco. The presence of Hg2+ did not cause considerable morphological abnormalities in the transgenic tobacco, which grew, flowered, and set seed similarly to the wild-type tobacco on the medium containing normally toxic levels of Hg2+. The ppk-transgenic tobacco showed more resistance to Hg2+ and accumulated more mercury than its wild-type progenitors. These results suggest that ppk-specified polyphosphate has abilities to reduce mercury toxicity, probably via chelation mechanism, and also to accumulate mercury in the transgenic tobacco. Based on the results obtained in the present study, the expression of ppk gene in transgenic tobacco plants might provide a means for phytoremediation of mercury pollution.