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）：含有高浓度有毒重金属（如镉、砷、铅和汞）的土壤和水域对人类和环境健康有害。这四种金属（类）是超级基金的七大优先危险物质之一。最近的研究和应用表明，植物通过根系吸收重金属并在植物枝条中积累重金属可以为重金属污染土壤和水体的去除和修复提供一种经济有效的方法。然而，植物重金属过度积累的许多基因、机制和途径仍有待鉴定和表征。植物螯合肽是植物中主要的重金属和类金属螯合和解毒硫酸肽。在最近的研究中，我们在了解植物重金属解毒和转运机制方面取得了进展，包括植物螯合素合成酶基因的分离、镉从根到茎的转移机制的表征、重金属积累突变体的分离、一种新的基于微阵列的快速突变克隆方法的发展和基于微阵列的可能有助于重金属运输的推定转运基因的鉴定。研究人员将验证以下假设：植物螯合素影响有毒金属在根到叶的长距离维管运输；新型有毒金属积累的表征