Cadmium (Cd) is a toxic non-essential elements to plants, and its accumulation in plants can affect human health through the food chain. Glycinebetaine (GB) is an effective osmotic adjustment substance for plants to resist abiotic stress, and it plays important roles in various stresses. To investigate whether endogenous GB accumulation in vivo can enhance Cd tolerance, we used betaine aldehyde dehydrogenase (BADH) transgenic tobacco plants to explore the important role of GB under Cd stress conditions. The results showed that the tobacco exposed to cadmium stress, lead to growth inhibition and biomass reduction, decreased photosynthesis, decreased the absorption of essential minerals and increased oxidative stress. However, GB accumulation in transgenic tobacco plants significantly increased Cd tolerance, as evidenced by the decreased growth inhibition, enhanced photosynthetic rate and reduced reactive oxygen species accumulation. GB can regulate Cd uptake and transport, which results in reduced Cd accumulation. Moreover, GB also reduced K⁺ efflux under Cd stress and regulated ion transporter genes to maintain element balance. Our findings provide a novel role of GB in enhancing Cd stress tolerance in transgenic plants and thus propose GB as a potential candidate for relieving Cd toxicity in other crops.

镉（Cd）是一种对植物有害的非必需元素，其在植物中的积累可通过食物链影响人体健康。甘氨酸甜菜碱（GB）是植物抵抗非生物胁迫的有效渗透调节物质，在各种胁迫中发挥重要作用。研究内源性GB在体内的积累可以增强 Cd 耐受性，我们使用甜菜碱醛脱氢酶 (BADH) 转基因烟草植物来探索 GB 在 Cd 胁迫条件下的重要作用。结果表明，暴露于镉胁迫下的烟草会导致生长抑制和生物量减少，光合作用减少，必需矿物质的吸收减少，氧化应激增加。然而，转基因烟草植物中 GB 的积累显着增加了 Cd 耐受性，这可以通过生长抑制减少、光合速率增强和活性氧积累减少来证明。GB 可以调节 Cd 的吸收和运输，从而减少 Cd 的积累。此外，GB 还减少了 K ⁺镉胁迫下的外排和调节离子转运蛋白基因以维持元素平衡。我们的研究结果提供了 GB 在增强转基因植物中 Cd 胁迫耐受性方面的新作用，因此提出 GB 作为减轻其他作物中 Cd 毒性的潜在候选者。