阐明作物镉（Cd）积累的遗传机制和培育低积累型新品种是根本上解决农业生产中土壤Cd污染问题的关键。大麦（Hordeum vulgare）是全球第四大禾谷类作物，揭示大麦Cd积累的生理机制对大麦遗传改良具有重要意义。在前期研究HvNramp5转运子的功能基础上，将深入解析待解决的三个科学问题：1. HvNramp5序列多态性及表达量差异与其Cd吸收能力的关系；2. HvNramp5不同单倍型转运蛋白对Cd转运的亲和性差异；3. HvNramp5表达受缺Fe诱导的转录调控机制。本项目拟对100份栽培大麦世界核心种质开展HvNramp5序列多态性分析，鉴定低Cd积累的基因单倍型；并利用酵母单杂交筛选参与调控HvNramp5转录的互作因子，揭示其表达受缺Fe诱导的转录调控机制。本研究结果将揭示大麦Cd积累基因型差异和HvNramp5的转录调控机制，不仅丰富作物抗逆理论，并为大麦遗传改良提供参考。

Understanding of the genetic mechanisms of cadmium (Cd) accumulation in crops and development of low Cd-contaminated cultivars are imperative for fundamentally solving the problem in agriculture caused by soil Cd pollution. Barley (Hordeum vulgare) is the fourth most important cereal crop globally after wheat, maize and rice, and it is huge potential risk of Cd contamination in barley. Therefore, revealing of the physiological mechanisms associated with Cd accumulation in barley is quite helpful for developing low Cd-contaminated cultivars. Based on our previous studies on the function of transporter HvNramp5, in the current project, three unknown aspects will be solved by further studies: 1. The sequence polymorphism of HvNramp5 and the relationship between the sequence polymorphism/gene expression and Cd uptakes in 100 barley cultivars; 2. The difference of Cd transport affinity of HvNramp5 haplotypes; 3. The mechanism of transcriptional regulation of HvNramp5 induced by Fe deficiency. Thus, the sequence polymorphism of HvNramp5 gene in 100 barley cultivars will be analyzed, and the gene haplotypes associated with low Cd accumulation are identified. The transport affinity of HvNramp5 haplotypes is compared to reveal its difference on Cd uptakes. Furthermore, the interaction factors of transcription factors with HvNramp5 are screened by Yeast-One-Hybrid system to explore the mechanism of transcriptional regulation of HvNramp5. It may be expected that the obtained results will reveal the genotypic variation and the mechanisms of transcriptional regulation of HvNramp5, and should innovate the theory of stress tolerance in plants and provide useful reference for breeding of barley cultivars with low Cd accumulation.