天然抗性相关巨噬细胞蛋白（Nramp）是存在于所有生物体（包括微生物、动物和植物）中的一个二价金属离子膜转运蛋白家族，也是重金属镉（Cd）进入植物根细胞的主要转运蛋白。三七（Panax notoginseng）作为云南省最具特色的中药资源大品种，对Cd具有较强的吸收富集能力，但吸收转运的分子机制尚不清楚。本项目在前期鉴定到一个可能参与三七Cd吸收转运的PnNramp3基因的基础上，拟通过生物信息学、生物化学和分子生理学等手段，对三七Nramp家族7个基因成员在Cd吸收转运中的分子特征，底物选择性与效率，功能偏好性与冗余性等进行系统研究，阐明Nramp家族基因在介导三七Cd吸收转运中的作用功能，并从蛋白结构、修饰和功能的角度，揭示三七Nramp家族基因可能的Cd选择性靶点和潜在分子机理，为生产上通过现代生物技术和分子育种技术培育低Cd低累三七新种质提供marker基因和选择位点。

Natural Resistance-Associated Macrophage Proteins (Nramp) belong to bivalent metal ion-transport membrane protein family that exists in all organisms (including microorganisms, animals and plants). They are also major transporters of heavy metal cadmium (Cd) into plant root cells. Panax notoginseng, the most distinctive large variety of traditional Chinese medicine in Yunnan Province, has a strong ability to uptake and enrich Cd, but the molecular mechanism underlying Cd uptake and transport in P. notoginseng is still unknown. Based on previous identification of PnNramp3 that may be involved in Cd uptake and transport in P. notoginseng, this project will systematically study the molecular characteristics, substrate selectivity and efficiency, functional preference and redundancy of seven Nramp members in P. notoginseng during Cd uptake and transport by means of bioinformatics, biochemistry and molecular physiology. The aim is to elucidate the functions of Nramp family genes in mediating Cd uptake and transport in P. notoginseng, and to reveal the possible Cd selective targets and potential molecular mechanisms of Nramp family genes in P. notoginseng from the point of protein structure, modification and function.The research will provide marker genes and selection sites for breeding new germplasm of P. notoginseng with low Cd accumulation through modern biotechnology and molecular breeding technology.