近年来水稻镉污染问题已成为社会的热点，对我国粮食安全生产和人民健康构成了巨大的威胁。探明水稻低镉积累分子生理，对保障水稻安全生产意义重大。前期我们通过全基因组关联分析鉴定到一个与谷粒镉积累有关的主效QTL（qCd3-2），进一步通过基因注释、基因差异表达分析、基因结构分析和酵母试验确定其候选基因为OsNRAMP2。本项目将在前期研究基础上，通过基因敲除、增量表达等转基因技术确认OsNRAMP2在水稻谷粒镉积累中的功能；通过不同生育期和器官组织中的镉含量，以及OsNRAMP2的表达特征分析OsNRAMP2在水稻谷粒镉积累过程的调控机理；通过分析OsNRAMP2基因型和表达对水稻谷粒镉积累和重要农艺性状的影响，以了解OsNRAMP2在水稻育种中的应用前景。项目的成功实施可为水稻谷粒镉积累分子机理的阐明提供新的知识，并为低镉水稻的分子育种奠定基础。

In the past few years, cadmium contamination of rice grain has been a hot topic in China and brings great threats to the safety of food production and people’s health. It is critical to understand the molecular and physiological mechanisms of low cadmium accumulation for safety rice production. In the previous study, we have identified a major QTL associated with cadmium accumulation in grain, designated as qCd3-2. The candidate gene, OsNRAMP2 was determined based on gene annotation, differential gene expression analysis, gene sequence analysis and yeast experiments. In this proposed project, gene knockout and overexpression will be used to confirm the function of OsNRAMP2 in grain cadmium accumulation in rice; the regulatory mechanism of OsNRAMP2 in grain cadmium accumulation in rice will be investigated through integrated analysis of the cadmium contents and expression levels in various tissues at different growth stage. In addition, the effects of different alleles and their expression levels of OsNRAMP2 on grain cadmium accumulation and some important agronomic traits will be analyzed to evaluate its potential use in rice production. With the successful completion of this project, it will provide new insights in the molecular and physiological mechanisms of grain cadmium accumulation in rice, and laydown basis for molecular breeding for low grain cadmium accumulation in rice.