Wang Yu, Li Xin, Zhuang Kai, Peng Yizhe, Huang Xueying, Lu Qian, Qian Meng, Liu Yanli, Chen Xin, Peng Kejian, Shen Zhenguo, Xia Yan
College of Life Sciences, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource, Nanjing Agricultural University, Nanjing, 210095, PR China.
Jinpu Landscape Architecture Limited Company, Nanjing, 211100, PR China.
Plant Physiol Biochem. 2025 Mar;220:109458. doi: 10.1016/j.plaphy.2024.109458. Epub 2024 Dec 26.
Long-term cadmium (Cd) exposure inhibits plant growth and development, reduces crop yield and quality, and threatens food security. Exploring the Cd tolerance mechanisms and safe production of crops in Cd-contaminated environment has become a worldwide concern. In this study, mung bean (Vigna radiata L.) cultivar Sulu (SL) and its three mutant lines (20#, 09#, and 06#) were used to compare the difference in Cd absorption, accumulation, and tolerance through pot and field experiments. 20#, 09#, and 06# are Cd-tolerant germplasms of mung bean but exist in different Cd tolerance mechanisms, 20# exhibited the lowest Cd absorption capacity, 09# possessed lower Cd translocation capacity, while 06# accumulated more Cd in protoplasts. Mung bean germplasms with higher Cd tolerance generally showed lower absorption capacity and intracellular accumulation of Cd. Besides, Cd accumulation in mung bean seeds is mainly depended on the absorption and translocation of Cd in roots and the Cd concentration in leaves, exogenous Mn supply inhibited the Cd net influx of roots and Cd accumulation in seeds, this trend was more pronounced in mung bean germplasms with higher Cd accumulation and absorption. Moreover, we characterized a Cd transporter gene VrNramp5, which was differentially expressed in different mung bean lines, overexpression of VrNramp5 increased Cd accumulation and was accompanied by Cd-sensitive phenotype in transgenic mung bean seedlings, and the Cd concentration of mung bean was significantly positively correlated with the expression levels of VrNramp5. Taken together, our findings demonstrated that different Cd tolerance mechanisms exist in mung bean. 20# is the new Cd-tolerant germplasm with low Cd absorption capacity and Cd accumulation in seeds, and has great potential for the safe production of mung bean in Cd-contaminated soils and the breeding of low Cd accumulation crop cultivars.
长期镉（Cd）暴露会抑制植物生长发育，降低作物产量和品质，威胁粮食安全。探索镉污染环境下作物的耐镉机制及安全生产已成为全球关注的问题。本研究通过盆栽和田间试验，利用绿豆（Vigna radiata L.）品种苏绿（SL）及其三个突变系（20#、09#和06#）比较镉吸收、积累和耐受性的差异。20#、09#和06#是绿豆的耐镉种质，但存在不同的耐镉机制，20#表现出最低的镉吸收能力，09#具有较低的镉转运能力，而06#在原生质体中积累更多的镉。镉耐受性较高的绿豆种质通常表现出较低的镉吸收能力和细胞内积累。此外，绿豆种子中的镉积累主要取决于根系对镉的吸收和转运以及叶片中的镉浓度，外源锰供应抑制了根系的镉净流入和种子中的镉积累，这种趋势在镉积累和吸收较高的绿豆种质中更为明显。此外，我们鉴定了一个镉转运基因VrNramp5，它在不同绿豆品系中差异表达，VrNramp5的过表达增加了镉积累，并伴随着转基因绿豆幼苗的镉敏感表型，绿豆中的镉浓度与VrNramp5的表达水平显著正相关。综上所述，我们的研究结果表明绿豆存在不同的耐镉机制。20#是具有低镉吸收能力和种子中镉积累的新型耐镉种质，在镉污染土壤中绿豆安全生产及低镉积累作物品种选育方面具有巨大潜力。
