College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310018, China; Instrumental Analysis Center of Zhejiang Gongshang University, Hangzhou 310018, China.
J Hazard Mater. 2020 Jun 5;391:122189. doi: 10.1016/j.jhazmat.2020.122189. Epub 2020 Jan 25.
Soil cadmium (Cd) accumulation presents risks to crop safety and productivity. However, through an exogenous application of abscisic acid (ABA), its accumulation in plants can be reduced and its toxicity mitigated, thereby providing an alternative strategy to counteract Cd contamination of arable soil. In the present study, we demonstrated that exogenous ABA application alleviates Cd-induced growth inhibition and photosynthetic damage in wild-type (Col-0) Arabidopsis plants. However, these positive effects were weakened in the ABA-importing transporter (AIT1)-deficient mutant (ait1). Through further analysis, we found that upon ABA application, the decrease in Cd level significantly differed among ait1, Col-0, and the two AIT1-overexpressing transgenic plants (AIT1ox-1 and AIT1ox-2), suggesting that AIT1 mediates the Cd-reducing effects of ABA. ABA application also inhibited the expression of IRT1, ZIP1, ZIP4, and Nramp1 in Col-0 plants subjected to Cd stress. However, significant differences among the genotypes (ait1, Col-0 and AIT1ox) were only observed in terms of IRT1 expression. Overall, our findings suggest that the suppression of Cd accumulation and restoration of plant growth by exogenous ABA require the ABA-importing activity of AIT1 to inhibit IRT1 expression.
土壤镉（Cd）积累对作物安全和生产力构成威胁。然而，通过外源施加脱落酸（ABA），可以减少植物对 Cd 的积累，减轻其毒性，从而为应对耕地土壤 Cd 污染提供了一种替代策略。本研究表明，外源 ABA 处理可缓解野生型（Col-0）拟南芥植株中 Cd 诱导的生长抑制和光合损伤。然而，在 ABA 转运蛋白（AIT1）缺失突变体（ait1）中，这些积极作用被削弱。通过进一步分析，我们发现 ABA 处理后，AIT1、Col-0 和两个 AIT1 过表达转基因植物（AIT1ox-1 和 AIT1ox-2）之间 Cd 水平的降低存在显著差异，表明 AIT1 介导了 ABA 的 Cd 降低效应。ABA 处理还抑制了 Col-0 植株在 Cd 胁迫下 IRT1、ZIP1、ZIP4 和 Nramp1 的表达。然而，在 IRT1 表达方面，各基因型（ait1、Col-0 和 AIT1ox）之间存在显著差异。总体而言，我们的研究结果表明，外源 ABA 通过抑制 IRT1 表达来抑制 Cd 积累和恢复植物生长。
