Molecular Mechanisms of Heavy Metal Detoxification

重金属解毒的分子机制

• 批准号: 6897647
• 负责人: JULIAN I SCHROEDER
• 金额: $ 21.62万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6897647
• 关键词: Arabidopsis; Cruciferae; bioaccumulation; biological signal transduction; biological transport; cadmium; detoxification; field study; genetically modified plants; hazardous substances; heavy metals; high throughput technology; leaf; metal poisoning; microarray technology; molecular cloning; plants; root; soil pollution; toxicant screening

DESCRIPTION (provided by applicant): Soils and waters with high levels of toxic heavy metals such as cadmium, arsenic, lead and mercury are detrimental to human and environmental health. These 4 metal(loid)s are among the Superfund's top 7 priority hazardous substances. Recent research and applications indicate that uptake of heavy metals into plants via the root system and accumulation of heavy metals in plant shoots could provide a cost effective approach for toxic metal removal and remediation of heavy metal-laden soils and waters. However many genes, mechanisms and pathways that function in heavy metal over-accumulation in plants remain to be identified and characterized. Phytochelatins are major heavy metal and metalloid chelating and detoxifying thiolate peptides in plants. In recent research we have made advances at understanding mechanisms that contribute to heavy metal detoxification and transport in plants, including isolation of phytochelatin synthase genes, characterization of mechanisms for root to shoot transfer of cadmium, isolation of heavy metal accumulation Arabidopsis mutants, development of a novel microarray-based rapid mutant cloning approach and microarray-based identification of putative transporter genes that may contribute to heavy metal transport. The investigators will test the hypotheses that, phytochelatins affect long distance root to leaf vascular transport of toxic metals; characterization of new toxic metal accumulation mutants will lead to identification of rate-limiting steps that function in plant heavy metal accumulation; and heavy metal sensing and signal transduction mechanisms in plants are important for plant heavy metal resistance and accumulation. To test these hypotheses, the proposed project will, in Specific Aims 1 and 2, characterize novel physiological and molecular mechanisms of root to shoot transport of heavy metals and phytochelatins using physiological, genomic, biochemical and membrane transport analyses. By pursuing a new high-throughput screening approach in collaborative research, the investigators have identified Arabidopsis mutants that affect the accumulation of toxic metals in leaves. In Specific Aim 3, a newly developed genomic microarray-based rapid mutant mapping and cloning approach will be used to isolate selected heavy metal accumulation mutant genes and characterize the underlying mechanisms. Specific Aim 4 will be to characterize heavy metal biosensing and transduction mechanisms in plants using a luciferase reporter screen. Trials with contaminated soils from Superfund sites will be pursued in collaboration with Edenspace Corp (in Specific Aim 5), to assess the feasibility of monitoring bioavailable heavy metals and of hyperaccumulating heavy metals and metalloids into plant roots and shoots using transgenic and mutant plants generated in this research.

描述（由申请人提供）：土壤和沃茨中含有高水平的有毒重金属，如镉、砷、铅和汞，对人类和环境健康有害。这4种金属（铅）是超级基金的前7名优先危险物质。 近年来的研究和应用表明，植物通过根系吸收重金属，并在地上部积累重金属，为重金属污染土壤和沃茨的去除和修复提供了一种经济有效的途径。 然而，许多基因，机制和途径的功能在重金属过量积累的植物仍然是确定和表征。 植物螯合肽是植物体内主要的重金属和类金属螯合解毒肽。近年来，我们在重金属解毒和转运机制的研究方面取得了一些进展，包括植物螯合素合成酶基因的分离、镉的根向地上部转移机制的研究、重金属积累拟南芥突变体的分离、开发一种新的基于微阵列的快速突变体克隆方法和微阵列-基于鉴定可能有助于重金属转运的假定转运蛋白基因。 研究人员将检验以下假设：植物螯合素影响有毒金属从根到叶的长距离维管运输;新的有毒金属积累的表征 突变体将导致鉴定植物重金属积累的限速步骤，重金属传感和信号转导机制在植物重金属抗性和积累中是重要的。 为了验证这些假设，拟议项目将在具体目标1和2中，利用生理学、基因组学、生物化学和膜转运分析，表征重金属和植物螯合素从根到茎转运的新生理和分子机制。 通过在合作研究中追求一种新的高通量筛选方法，研究人员已经确定了影响叶片中有毒金属积累的拟南芥突变体。在具体目标3中，将使用新开发的基于基因组微阵列的快速突变定位和克隆方法来分离选定的重金属积累突变基因并表征潜在机制。具体目标4将是表征重金属生物传感和转导 机制在植物中使用荧光素酶报告屏幕。 将与Edenspace公司合作，对来自超级基金场地的污染土壤进行试验（在具体目标5中），以评估利用本研究中产生的转基因和突变植物监测生物可利用的重金属以及超积累重金属和类金属进入植物根和芽的可行性。