Phytoremediation of Pollutants Using Transgenic Plants

使用转基因植物对污染物进行植物修复

• 批准号: 7600508
• 负责人: Stuart E Strand
• 金额: $ 48.01万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7600508
• 关键词: Air; Air Pollutants; Beds; CYP3A4 gene; Carbon Tetrachloride; Chloroform; Chlorpyrifos; Cloning; Cultured Cells; Cytochrome P-450 CYP2E1; Cytochrome P450; Degradation Pathway; Equilibrium; Excision; Exposure to; Funding; Gene Expression; Genes; Genetic Transcription; Halogenated Hydrocarbons; Health; Human; Knowledge; Lead; Mammals; Metabolism; Methods; Nervous system structure; Neurotoxins; Organophosphates; Organophosphorus Compounds; Pathway interactions; Pesticides; Plant Genes; Plant Roots; Plants; Predisposition; Protein Isoforms; Protein Overexpression; Proteins; Risk; Sequence Analysis; System; Testing; Transgenes; Transgenic Organisms; Transgenic Plants; Trees; Trichloroethylene; Water; Work; Yeasts; aryldialkylphosphatase; base; design; genome sequencing; oxidation; pollutant; programs; promoter; remediation; research study; response; size; uptake; volatile organic compound

Exposure to toxic volatile organic compounds (VOCs) continues to pose a significant risk to human health. Halogenated VOCs such as chloroform, carbon tetrachloride (CT) and trichloroethylene (TCE) are among the most common contaminants in water and air. These compounds share a susceptibility to oxidation by mammalian cytochrome P450 2E1. In past NIEHS-funded work, we have demonstrated that TCE and CT are oxidized by axenic poplar cell cultures using a pathway similar to that in mammals, and that poplar trees are able to take up and degrade VOCs. Our work has led to the realization that TCE and CT uptake by wild-type plants is too weak to significantly reduce their concentration in root zone water, motivating a search for plants with increased degradative activity toward VOCs. We have expressed mammalian cytochrome P450 2E1 in plants, achieving greater oxidation of TCE and greater removal of VOCs in several plants, including poplar. Our latest r2E1 aspen clones have up to 132-fold greater metabolism of TCE compared to control aspens. We are presently testing VOC degradation by transgenic poplar to identify superior clones for field-scale study. In the proposed work we will take transgenic poplar to test-bed scale, testing halogenated VOC uptake compared to wild-type by mass balance studies with full size trees. We will also test the ability of transgenic plants to remove VOCs from air. We will also continue analysis of wild-type plant metabolism of halogenated VOCs in poplar using the recently completed poplar genome sequence. Informed by the genome sequence, we will clone the poplar genes that are most similar to the mammalian genes known to be involved in degradation of pollutants. With overexpression of all genes in the pathway for degradation of TCE and other VOCs, we will produce transgenic plants with enhanced ability for remediation of VOCs in water and air. We will also use the genome sequence for analysis of genes that are upregulated in response to pollutants using poplar microarrays. These experiments are expected to yield important clues about which genes are involved in the degradation of pollutants. We expect these experiments to lead to the discovery of useful poplar promoters that will enable expression of detoxifying transgenes only when the substrates are present. New work will focus on the introduction into plants of genes for the degradation of organophosphorus neurotoxins. Mammalian cytochrome P450 isoforms have been shown to degrade organophosphorus compounds. We will use our existing poplar constructs containing CYP3A4 to determine whether chlorpyrifos is taken up and transformed. To optimize the system for degradation of organophosphorous compounds, we will express CYP3A4 and organophosphorus hydrolase, PON1. With our new knowledge of the genes involved in degradation of pollutants, we will be able to design superior plants for phytoremediation.

暴露于有毒的挥发性有机化合物（VOC）继续对人类健康构成重大风险。氯仿，四氯化碳（CT）和三氯乙烯（TCE）等卤代VOC是水和空气中最常见的污染物之一。这些化合物具有哺乳动物细胞色素P450 2E1的氧化敏感性。在过去的NIEHS资助工作中，我们证明了TCE和CT使用类似于哺乳动物的途径被轴突杨树细胞培养物氧化，并且杨树树可以占据并降级VOC。我们的工作已经意识到野生型的TCE和CT吸收 植物太弱，无法显着降低其在根区域水中的浓度，从而激发了对VOC降解活性增加的植物的搜索。我们在植物中表达了哺乳动物细胞色素P450 2E1，在包括杨树在内的几种植物中实现了更大的TCE氧化和更大的VOC去除。与对照毒药相比，我们最新的R2E1 ASPEN克隆的TCE代谢高达132倍。目前，我们正在测试转基因杨树的VOC降解，以识别出优质的克隆进行现场尺度研究。在拟议的工作中，我们将将转基因的杨树降至测试尺度，与具有全尺寸树木的质量平衡研究相比，与野生型相比，测试卤代VOC的吸收。我们还将测试转基因植物从空中删除VOC的能力。我们还将使用最近完成的杨树基因组序列继续分析杨树中卤代VOC的野生型植物代谢。通过基因组序列的告知，我们将克隆与已知参与污染物降解的哺乳动物基因最相似的杨树基因。随着TCE和其他VOC降解途径中所有基因的过表达，我们将生产具有增强水和空气中VOC的能力的转基因植物。我们还将使用基因组序列进行分析，这些基因被响应上调 使用杨树微阵列污染物。预计这些实验将产生重要的线索，涉及哪些基因参与污染物的降解。我们期望这些实验会导致发现有用的杨树启动子，该启动子只有在存在底物时才能表达解毒转基因。新的工作将集中于在基因植物中引入有机磷神经毒素的降解。哺乳动物细胞色素P450同工型已被证明可降解有机磷化合物。我们将使用包含CYP3A4的现有杨树构造来确定是否占用并转化了毒死rif。为了优化有机磷化合物降解的系统，我们将表达CYP3A4和有机磷水解酶PON1。借助我们对污染物降解的基因的新知识，我们将能够为植物修复设计出色的植物。