Cadmium (Cd) is a highly toxic non-essential element, which requires the transporters of essential and beneficial elements to enter the plant, and poses threat to plant growth and development. However, the mechanism of Cd uptake and accumulation in mungbean is limited. Here, we reported a Cd transporter VrNramp5 in mungbean, and its functional roles in response to Cd toxicity were conducted. The expression of was down-regulated by Cd toxicity. VrNramp5 localized at plasma membrane based on subcellular localization analysis in epidermal cells of . Heterologous expression of in promoted Cd accumulation, displayed the Cd sensitive phenotype including decreased root elongation and fresh weight, and could diminish the Cd tolerance phenotype of -deficient mutant (). Non–invasive micro–test showed that overexpressing lines possessed higher Cd absorption capacity in root tips. Moreover, the Cd fluorescence probe staining revealed that more Cd accumulated in the leaf protoplasts of -overexpressing Arabidopsis. Those were consistent with the plants grown in the absence or presence of Cd (10 mg kg or 20 mg kg) in soil. Taken together, is responsible for plant Cd tolerance via regulating the Cd absorption capacity of roots and altering the intracellular distribution of Cd. Our findings provide a theoretical basis for further exploring the mechanism of Cd tolerance and breeding variety of mungbean with low Cd accumulation.

中文翻译：

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绿豆质膜定位转运蛋白 VrNramp5 控制拟南芥的镉耐受性和积累

镉（Cd）是一种剧毒的非必需元素，需要必需和有益元素的转运蛋白进入植物体内，对植物的生长发育构成威胁。然而，绿豆对Cd的吸收和积累机制有限。在这里，我们报道了绿豆中的镉转运蛋白VrNramp5，并对其响应镉毒性的功能作用进行了研究。 Cd 毒性下调了 的表达。根据表皮细胞的亚细胞定位分析，VrNramp5 定位于质膜。 in的异源表达促进Cd积累，表现出Cd敏感表型，包括根伸长和鲜重降低，并且可以降低缺陷突变体的Cd耐受表型（）。非侵入性微量测试表明，过表达株系的根尖具有更高的镉吸收能力。此外，Cd荧光探针染色显示，过量表达的拟南芥叶片原生质体中积累了更多的Cd。这些结果与土壤中缺乏或存在 Cd（10 mg kg 或 20 mg kg）的情况下生长的植物一致。总的来说，它通过调节根部的镉吸收能力和改变细胞内镉的分布来负责植物的镉耐受性。该研究结果为进一步探讨绿豆耐镉机制及选育低镉积累品种提供了理论依据。