Regulation of cadmium tolerance and accumulation by miR156 in Arabidopsis
Regulation of cadmium tolerance and accumulation by miR156 in Arabidopsis
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拟南芥中 miR156 对镉耐受和积累的调控
DOI：
10.1016/j.chemosphere.2019.125168
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Gang Wu
中科院分区：
文献类型：
--
作者：
Lu Zhang;Han Ding;Hailing Jiang;Huasen Wang;Kexin Chen;Jinju Duan;Shengjun Feng;Gang Wu
植物已经进化出有效的策略来应对重金属镉的毒性，但镉耐受和积累的调控机制仍然知之甚少。 miR156 已被证明是植物发育和胁迫反应的主要调节因子。然而，miR156是否也参与植物镉胁迫反应仍不清楚。在这里，我们发现过表达 miR156 (miR156OE) 的植物在芽中积累的 Cd 显着减少，并增强了对 Cd 胁迫的耐受性。 miR156 (MIM156) 水平被敲低的植物对镉胁迫敏感，并且积累了显着更高的镉。在Cd胁迫下，miR156OE具有显着更长的初生根长度、更高的生物量和叶绿素含量、抗氧化酶活性增加和内源活性氧（ROS）水平降低，而MIM156具有相反的表型。为了研究拟南芥中 miR156 介导的镉胁迫反应的潜在机制，我们分析了几个镉转运蛋白基因的表达。 miR156OE中Cd摄取转运蛋白AtZIP1、AtZIP2和液泡分离转运蛋白AtABCC1的表达显着升高，而在MIM156中显着降低。 MIM156还导致AtHMA4水平升高，AtHMA4负责将Cd从根运输到芽。我们的结果表明，miR156 通过调节 ROS 水平和 Cd 吸收/转运基因表达，作为植物对 Cd 胁迫耐受性的正调节因子。因此，我们的研究为植物中的镉转运和耐受性增加了一层新的调控机制，并为利用miR156调节植物营养生长和发育来人为调控镉转运提供了视角。
Plants have evolved effective strategies to cope with heavy metals Cd toxicity, but the regulatory mechanism underlying Cd tolerance and accumulation are still poorly understood. miR156 has been shown to be the master regulator of development and stress response in plants. However, whether miR156 is also involved in plant Cd stress response remains unknown. Here, we show that plants overexpressing miR156 (miR156OE) accumulated significantly less Cd in the shoot, and conferred enhanced tolerance to Cd stress. Plants with a knocked-down level of miR156 (MIM156) were sensitive to Cd stress, and accumulated significantly higher Cd. Under Cd stress, miR156OE had significantly longer primary root length, higher biomass and chlorophyll content, increased activities of antioxidative enzymes and lower levels of endogenous reactive oxygen species (ROS), while MIM156 had the opposite phenotype. To investigate the underlying mechanism of miR156-mediated Cd stress response inArabidopsis, we profiled the expression of several Cd transporter genes. The expression of Cd uptake transporter ofAtZIP1,AtZIP2and vacuole segregated transporterAtABCC1was significantly elevated in miR156OE, whereas it was significantly reduced in MIM156. MIM156 also led to an elevated level ofAtHMA4responsible for transporting Cd from the root to the shoot. Our results indicate that miR156 acts as a positive regulator of plant tolerance to Cd stress by modulating ROS levels and Cd uptake/transport genes expression. Therefore, our study adds a new layer of regulatory mechanism for Cd transport and tolerance in plants, and provides a perspective to regulate Cd transport artificially by modulating plant vegetative growth and development using miR156.