Project 5: Phytorermediation of Pollutants Using Transgenic Plants

接触有毒挥发性有机化合物(VOCs)继续对人类健康构成重大威胁。 VOCs，如氯仿、四氯化碳(CT)和三氯乙烯(TCE)，以及苯和 其他单环芳烃是水和空气中最常见的污染物之一。这些化合物 与哺乳动物肝脏细胞色素P450 2E1一样，对氧化也很敏感。在过去NIEHS资助的 在威斯康星州大学的工作中，我们已经证明了TCE和CT被无菌杨树细胞培养氧化，使用 与哺乳动物相似的途径，野生型杨树能够吸收和降解TCE和CT。 我们的工作使人们认识到，野生植物对TCE和CT的吸收太弱，无法显著 降低它们在根区水中的浓度，为植物的发育提供动力 增加了对VOCs的降解活性。为此，我们表达了哺乳动物细胞色素 植物中的P450 2E1(细胞色素P450 2E1)，在转基因杨树中实现了对TCE的更大数量级的氧化。 我们目前正在进行野生型杨树和转基因杨树对三氯乙烯的田间降解试验 能够进行质量平衡测量的试验台设备中的刻度。在本应用程序中，我们建议使用 具体目标如下：比较野生型和已有的转基因杨树品系的抗病能力 在田间试验中降解三氯乙烯、四氯乙烯和四氯乙烯；识别因污染物的存在而上调的基因； 克隆和分析参与TCE及其代谢物降解的植物基因；确定 三氯乙烯和苯在转基因杨树中的代谢产物提高挥发性有机物的吸收 增加叶表面开放气孔的数量，表达有机磷羟基酶， 植物中的对氧磷酶PON1，用于降解有机磷神经毒素；并测定其生态毒性 对转基因植物根际、叶凋落物和根际土壤蚯蚓的暴露 向VOC致敬。

Exposure to toxic volatile organic compounds (VOCs) continues to pose a significant risk to human health. VOCs such as chloroform, carbon tetrachloride (CT) and trichloroethylene (TCE), along with benzene and other single-ring aromatics are among the most common contaminants in water and air. These compounds share a susceptibility to oxidation by the mammalian hepatic cytochrome P450 2E1. In past NIEHS-funded work at UW, we have demonstrated that TCE and CT are oxidized by axenic poplar cell cultures using a pathway similar to that in mammals, and that wild-type poplar are able to take up and degrade TCE and CT. 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, providing motivation for the development of plants with increased degradative activity toward VOCs. Toward this end we have expressed mammalian cytochrome P450 2E1 (CYP2E1) in plants, achieving orders of magnitude greater oxidation of TCE in transgenic poplar. We are presently engaged in testing TCE degradation by wild-type and CYP2E1 transgenic poplar at field scale in a test bed facility capable of mass balance measurements. In this application we propose the following specific aims: compare the abilities of wild-type and existing CYP2E1 transgenic poplar lines to degrade TCE, CT, and PCE in field tests; identify genes that are up-regulated by the presence of pollutants; clone and analyze the plant genes involved in the degradation of TCE and its metabolites; determine the metabolites of TCE and benzene in CYP2E1 transgenic poplar; increase the uptake of VOCs from the air by increasing the number of open stomata on leaf surfaces; express the organophosphorus hydroxylase, paraoxonase PON1, in plants for the degradation of organophosphate neurotoxins; and determine the ecotoxicity to earthworms of root materials, leaf litter and rhizosphere soil of CYP2E1 transgenic plants exposed to VOCs.