Toward detoxifying mercury-polluted aquatic sediments with rice genetically engineered for mercury resistance
Toward detoxifying mercury-polluted aquatic sediments with rice genetically engineered for mercury resistance
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DOI：
10.1897/02-442
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发表时间：
2003-12-01
影响因子：
4.1
通讯作者：
Meagher, RB
中科院分区：
文献类型：
--
作者：
Heaton, ACP;Rugh, CL;Meagher, RB
土壤和水的汞污染在美国和世界各地的许多地方都是一个严重的问题。表达细菌汞还原酶基因mer-A的植物物种将生长基质中的离子汞Hg（II）转化为毒性较小的金属汞Hg（0）。这种活性赋予植物抗汞性，并通过挥发将汞从植物和基质中去除。我们的目标是开发植物，拦截和消除汞（II）从污染的水生系统之前，它可以进行细菌介导的甲基化的神经毒性甲基汞。因此，将单子叶植物启动子控制下的met-A基因导入水稻中。（水稻）用粒子枪轰击。这是第一个单子叶植物和第一个湿地适应物种表达基因。表达merA的水稻在半固体生长培养基上发芽并生长，培养基中加入了足够的Hg（II）以杀死非工程化（野生型）对照。为了证实抗性机制是Hg（II）向Hg（0）的转化，将表达merA的O.在掺入Hg（II）的液体培养基或水饱和的土壤培养基中生长，结果表明，与野生型对应物相比，它们挥发性地显著携带Hg（0）。进一步的基因操作可以提高植物提取土壤中Hg（II）的效率，并将其挥发为Hg（0），或者具有将甲基汞直接转化为Hg（0）的新能力。
Mercury contamination of soil and water is a serious problem at many sites in the United States and throughout the world. Plant species expressing the bacterial mercuric reductase gene, mer-A, convert ionic mercury, Hg(II), from growth substrates to the less toxic metallic mercury, Hg(0). This activity confers mercury resistance to plants and removes mercury from the plant and substrates through volatilization. Our goal is to develop plants that intercept and remove Hg(II) from polluted aquatic systems before it can undergo bacterially mediated methylation to the neurotoxic methylmercury. Therefore, the met-A gene under the control of a monocot promoter was introduced into Oryza sativa L. (rice) by particle gun bombardment. This is the first monocot and first wetland-adapted species to express the gene. The merA-expressing rice germinated and grew on semisolid growth medium spiked with sufficient Hg(II) to kill the nonengineered (wild-type) controls. To confirm that the resistance mechanism was the conversion of Hg(II) to Hg(0), seedlings of merA-expressing O. sativa were grown in Hg(II)-spiked liquid medium or water-saturated soil media and were shown to volatilize significantly bore Hg(0) than wild-type counterparts. Further genetic manipulation could yield plants with increased efficiency to extract soil Hg(II) and volatilize it as Hg(0) or with the novel ability to directly convert methylmercury to Hg(0).