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.

接触有毒挥发性有机化合物（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) 等卤化 VOC 是水和空气中最常见的污染物。这些化合物都对哺乳动物细胞色素 P450 2E1 的氧化敏感。在过去 NIEHS 资助的工作中，我们已经证明，TCE 和 CT 通过与哺乳动物类似的途径被无菌杨树细胞培养物氧化，并且杨树能够吸收和降解 VOC。我们的工作使我们认识到野生型对 TCE 和 CT 的吸收 植物太弱，无法显着降低其在根区水中的浓度，这促使人们寻找对挥发性有机化合物具有更强降解活性的植物。我们在植物中表达了哺乳动物细胞色素 P450 2E1，在包括杨树在内的多种植物中实现了 TCE 的更大氧化和 VOC 的更大去除。与对照白杨相比，我们最新的 r2E1 白杨克隆的 TCE 代谢量高出 132 倍。我们目前正在测试转基因杨树对 VOC 的降解作用，以确定用于田间规模研究的优质克隆。在拟议的工作中，我们将把转基因杨树进行试验台规模，通过对全尺寸树木进行质量平衡研究，测试与野生型相比的卤化挥发性有机化合物的吸收量。我们还将测试转基因植物去除空气中挥发性有机化合物的能力。我们还将利用最近完成的杨树基因组序列继续分析杨树中卤化 VOC 的野生型植物代谢。根据基因组序列，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。通过过度表达TCE和其他VOCs降解途径中的所有基因，我们将生产出具有增强的水和空气中VOCs修复能力的转基因植物。我们还将使用基因组序列来分析响应上调的基因 使用杨树微阵列来检测污染物。这些实验有望提供有关哪些基因参与污染物降解的重要线索。我们期望这些实验能够发现有用的杨树启动子，这些启动子只有在底物存在时才能表达解毒转基因。新的工作将集中于将有机磷神经毒素降解的基因引入植物。哺乳动物细胞色素 P450 亚型已被证明可以降解有机磷化合物。我们将使用现有的含有 CYP3A4 的杨树构建体来确定毒死蜱是否被吸收和转化。为了优化有机磷化合物的降解系统，我们将表达 CYP3A4 和有机磷水解酶 PON1。凭借我们对污染物降解相关基因的新知识，我们将能够设计出用于植物修复的优质植物。