钙、铁、锌等矿质元素是人体必需的营养元素。然而，全世界有超过三分之二的人口存在一种或多种必需矿质营养元素摄入不足的问题，由此造成的“隐性饥饿”已成为影响人类健康的全球性问题。水稻作为重要粮食作物之一，不仅为世界人口提供超过五分之一的能量，同时也是矿质营养元素的主要来源。挖掘水稻籽粒矿质元素积累相关基因，培育籽粒富含矿质营养元素的生物强化水稻品种将有助于缓解缺钙等矿质营养元素缺乏的问题。在前期工作中，我们利用两个水稻定位群体定位到了134个控制16种元素在籽粒中积累的QTL，包括4个控制籽粒钙含量的QTL。本项目将对其中一个贡献率最高达57.1%的主效QTL进行精细定位，克隆相关基因，阐明该基因的功能、作用机制及其控制水稻籽粒钙含量的分子机理和调控网络。本项目将对理解水稻中钙的迁移及其在籽粒中积累的分子机理具有重要意义，并为进一步通过分子标记辅助育种等手段培育籽粒高钙水稻品种提供理论指导。

Mineral elements such as calcium, iron, zinc are essential for human’s wellbeing. However, it is estimated that over two-thirds of the world’s population lack one or more essential mineral elements. Currently, mineral malnutrition, better known as “hidden hunger”, is considered to be one of the most serious global challenges to humankind. Rice is one of the most important staple crops, providing more than one fifth of daily calories for half of the world’s human population as well as being a major source of mineral nutrients. Biofortification of rice varieties with mineral nutrients through breeding is considered to be a cost-effective strategy to alleviate micronutrient malnutrition such as calcium deficiency. Such strategy is based on the identification of QTLs/genes that control the accumulation of mineral nutrients in rice grains. We have previously identified 134 QTLs that control the variations in the concentrations of 16 mineral elements in unmilled rice grain by using two synthetic rice mapping populations. Among the identified four QTLs that control calcium accumulation in rice grain, one QTL was identified in both mapping populations on multiple years. This QTL explains up to 57.1% of variation in grain calcium concentration. In this project, we aim to identify the gene responsible for this QTL, characterize the function of the causal gene, and elucidate the potential working mechanisms and regulatory networks. This project will shade light on the molecular mechanisms for the regulation of calcium translocation and accumulation in rice grain, and provide genetic materials and basic knowledge for breeding rice varieties with high calcium in grains using strategies like molecular marker-assisted selection.