Phytoremediation of methylmercury pollution:: merB expression in Arabidopsis thaliana confers resistance to organomercurials
Phytoremediation of methylmercury pollution:: merB expression in Arabidopsis thaliana confers resistance to organomercurials
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DOI：
10.1073/pnas.96.12.6808
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发表时间：
1999-06-08
影响因子：
11.1
通讯作者：
Meagher, RB
中科院分区：
文献类型：
--
作者：
Bizily, SP;Rugh, CL;Meagher, RB
甲基汞是一种环境毒物，可生物放大并导致动物严重的神经退化。它是由被汞污染的土壤和沉积物中的细菌产生的。为了探索植物提取和解毒这种化学物质的潜力，我们设计了一种模式植物，拟南芥，表达一种修饰的细菌基因，merBpe，编码有机汞裂解酶（MerB）的植物启动子的控制下。MerB催化碳-汞键的质子分解，去除有机配体并释放Hg（II），这是一种移动的汞物质。表达merBpe的转基因植物在一甲基氯化汞和醋酸苯汞的浓度范围很广的情况下生长旺盛。缺乏merBpe基因的植物在相同的有机汞浓度下受到严重抑制或死亡。6个独立分离的转基因株系产生的merBpe mRNA和MerB蛋白水平在10- 15倍范围内变化，即使是最低水平的merBpe表达也能赋予对有机汞的抗性。我们的工作表明，本地水生植物（如，树木，灌木，草）工程表达merBpe可能会被用来降解甲基汞在污染的网站和螯合汞（II）为以后的去除。
Methylmercury is an environmental toxicant that biomagnifies and causes severe neurological degeneration in animals. It is produced by bacteria in soils and sediments that have been contaminated with mercury. To explore the potential of plants to extract and detoxify this chemical, we engineered a model plant, Arabidopsis thaliana, to express a modified bacterial gene, merBpe, encoding organomercurial lyase (MerB) under control of a plant promoter. MerB catalyzes the protonolysis of the carbon-mercury bond, removing the organic ligand and releasing Hg(II), a less mobile mercury species. Transgenic plants expressing merBpe grew vigorously on a wide range of concentrations of monomethylmercuric chloride and phenylmercuric acetate. Plants lacking the merBpe gene were severely inhibited or died at the same organomercurial concentrations. Six independently isolated transgenic lines produced merBpe mRNA and MerB protein at levels that varied over a 10- to 15-fold range, and even the lowest levels of merBpe expression conferred resistance to organomercurials. Our work suggests that native macrophytes (e.g,, trees, shrubs, grasses) engineered to express merBpe may be used to degrade methylmercury at polluted sites and sequester Hg(II) for later removal.