Molecular Mechanisms of Heavy Metal Detoxification

重金属解毒的分子机制

基本信息

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
项目类别：
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

项目摘要

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）：土壤和水中含有大量有毒重金属（例如镉、砷、铅和汞），对人类和环境健康有害。这 4 种金属（类金属）属于超级基金的 7 种优先危险物质。最近的研究和应用表明，通过根系将重金属吸收到植物中以及在植物芽中积累重金属可以为有毒金属去除和富含重金属的土壤和水体的修复提供一种经济有效的方法。然而，许多在植物重金属过度积累中起作用的基因、机制和途径仍有待鉴定和表征。植物螯合素是植物中主要的重金属和类金属螯合和解毒硫醇肽。在最近的研究中，我们在了解有助于植物重金属解毒和转运的机制方面取得了进展，包括植物螯合素合酶基因的分离、镉从根到芽转移机制的表征、重金属积累拟南芥突变体的分离、开发基于微阵列的新型快速突变克隆方法以及基于微阵列的可能有助于重金属转运的假定转运蛋白基因的鉴定。研究人员将测试以下假设：植物螯合素影响有毒金属从根到叶的长距离维管运输；新有毒金属积累的表征突变体将导致鉴定在植物重金属积累中起作用的限速步骤；植物体内的重金属传感和信号转导机制对于植物对重金属的抵抗和积累具有重要意义。为了检验这些假设，拟议项目将在具体目标 1 和 2 中，利用生理、基因组、生化和膜转运分析来表征重金属和植物螯合素从根到芽转运的新生理和分子机制。通过在合作研究中采用新的高通量筛选方法，研究人员已经确定了影响叶子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体作图和克隆方法来分离选定的重金属积累突变体基因并表征其潜在机制。具体目标 4 是表征重金属生物传感和转导使用荧光素酶报告筛选的植物机制。将与 Edenspace Corp 合作（在具体目标 5 中）对超级基金地点受污染的土壤进行试验，以评估监测生物可利用重金属以及使用在这项研究。