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。卤代VOC如氯仿、四氯化碳（CT）和三氯乙烯（TCE）是水和空气中最常见的污染物之一。这些化合物对哺乳动物细胞色素P450 2E1的氧化具有敏感性。在过去的NIEHS资助的工作中，我们已经证明，TCE和CT被纯白杨细胞培养物氧化，使用类似于哺乳动物的途径，白杨能够吸收和降解VOCs。我们的工作使人们认识到，野生型TCE和CT的摄取 植物太弱而不能显著降低它们在根区水中的浓度，这促使人们寻找对VOC具有增加的降解活性的植物。我们已经在植物中表达了哺乳动物细胞色素P450 2E1，在包括白杨在内的几种植物中实现了更大的TCE氧化和更大的VOC去除。我们最新的r2E1白杨克隆的TCE代谢比对照白杨高132倍。我们目前正在测试转基因白杨的VOC降解能力，以确定上级无性系进行实地研究。在拟议的工作中，我们将转基因白杨试验床规模，测试卤化VOC吸收相比，野生型的质量平衡研究与全尺寸的树木。我们还将测试转基因植物去除空气中VOC的能力。我们还将继续分析野生型植物代谢卤化挥发性有机化合物在白杨使用最近完成的白杨基因组序列。根据基因组序列，我们将克隆与已知参与降解污染物的哺乳动物基因最相似的白杨基因。通过过量表达TCE和其他VOCs降解途径中的所有基因，我们将培育出具有增强修复水和空气中VOCs能力的转基因植物。我们还将使用基因组序列分析基因的上调， to pollutants污染物using运用poplar白杨microarray微阵列.这些实验有望为研究哪些基因参与污染物的降解提供重要线索。我们希望这些实验能够发现有用的白杨启动子，使解毒转基因的表达，只有当底物存在。新的工作将集中在将降解有机磷神经毒素的基因引入植物。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。我们将使用我们现有的含有CYP3A4的白杨结构来确定毒死蜱是否被吸收和转化。为了优化降解有机磷化合物的系统，我们将表达CYP3A4和有机磷水解酶PON1。随着我们对污染物降解基因的新认识，我们将能够设计出用于植物修复的上级植物。