转运蛋白SaPCT在超积累植物富集镉过程中的功能研究

项目名称： 转运蛋白SaPCT在超积累植物富集镉过程中的功能研究

项目编号： No.31300211

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 张中春

作者单位： 华中师范大学

项目金额： 23万元

中文摘要： 我国环境重金属污染形势严峻，危害深远。植物螯合肽（PCs）是解除植物重金属毒害的重要有机生物分子，可作为配体参与重金属向液泡内转运，以及重金属在植物体内的长距离运输，但调控PCs进出细胞的转运蛋白迄今尚未发现。申请人前期在东南景天中克隆到一个潜在的质膜PCs转运蛋白基因SaPCT，发现该基因可能对超富集镉具有重要作用。本项目拟在此基础上，研究SaPCT转运PCs的动力学特性，鉴定SaPCT转运PCs的功能基团，揭示SaPCT转运底物的生化特征；研究SaPCT基因表达的组织特异性和蛋白亚细胞定位，筛选其转录因子，揭示SaPCT基因的表达与转录调控规律；进一步分析SaPCT基因的RNA干扰植株和嫁接植株富集镉的表型，阐明SaPCT在植株体内的功能。本研究有助于揭示SaPCT基因在东南景天超富集镉过程中的作用，为植物遗传改良提供基因资源和理论借鉴，以服务于环境重金属污染的治理。

中文关键词： 重金属；谷胱甘肽；OPT4；HMA2；

英文摘要： Heavy metal pollution is a national serious environmental problem. Phytochelatins (PCs), synthesized from glutathione by phytochelatin synthase, are necessary to detoxify heavy metals in plants. It has been established that PCs can work as the main ligands to mediate heavy metal sequestration in vacuoles and long-distance transport in plants. However, the plasma membrane transporters for PCs remain unknown up to now. In previous studies, SaPCT was screened as a new transporter for phytochelatins, and was supposed to play important roles in cadmium hyperaccumulation in hyperaccumulator Sedum alfredii. In the current proposal, the function of SaPCT will be investigated in S. alfredii. Firstly, analyze the kinetics of PC transport by SaPCT, and identify the specific amino acids for SaPCT to transport PCs. Secondly, study the tissue expression and subcellular localization of SaPCT, and screen the transcription factors in regulating expression of of SaPCT. Thirdly, analyze the phynotypes of RNAi and grafted S. alfredii in response to cadmium stress. This project will elucidate the fucntions of SaPCT in S. alfredii during cadmium hyperaccumulation, and can go towards the engineering plants for developing phytoremediation to clean heavy metal polluted sites.

英文关键词： heavy metal；glutathione；OPT4；HMA2；