Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, China.
Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, China.
Sci Total Environ. 2018 Dec 10;644:602-610. doi: 10.1016/j.scitotenv.2018.07.002. Epub 2018 Jul 11.
Although previous studies have indicated that selenium (Se) can reduce cadmium (Cd) uptake into rice, the mechanism at the cellular level has not been reported. Here, rice suspension cells exposed to Cd treatment in the presence or absence of Se were characterized. Compared with treatment with alone, pretreatment with Se increased the proportion of live cells by 83.1%. The levels of reactive oxygen species and mitochondrial membrane potential in the Se-pretreated rice cells were decreased by 86.6% and 76.0%, respectively. In addition, non-invasive micro-test technology suggested that the mean values of Cd influx decreased significantly in the Se-pretreated rice cells in a concentration-dependent manner. The results of inductively coupled plasma-mass spectrometry (ICP-MS) showed that 67.4%-78.8% Cd accumulated onto the cell walls of the pretreated-Se rice cells. The addition of Se increased the lignin content and thickness of the cell walls, leading to an improved mechanical force of the cell walls, as determined by atomic force microscopy (AFM). Furthermore, Se pretreatment decreased the expression of genes involved in Cd uptake (OsNramp5) and transport (OsLCT1) but activated the expression of genes involved in Cd transport into vacuoles (OsHMA3) and lignin synthesis (OsPAL, OsCoMT and Os4CL3). These results indicated that supplying Se alleviates Cd toxicity by regulating the express of lignin synthesis and Cd-related genes. The present findings provide new insights on a plausible explanation of the Se-reduced Cd uptake into rice.
尽管先前的研究表明硒（Se）可以减少水稻对镉（Cd）的吸收，但细胞水平的机制尚未报道。在这里，研究了暴露于 Cd 处理的水稻悬浮细胞，同时存在或不存在 Se。与单独处理相比，Se 的预处理使活细胞的比例增加了 83.1%。Se 预处理的水稻细胞中的活性氧和线粒体膜电位水平分别降低了 86.6%和 76.0%。此外，非侵入性微测试技术表明，Se 预处理的水稻细胞中 Cd 流入的平均值以浓度依赖的方式显著降低。电感耦合等离子体质谱（ICP-MS）的结果表明，67.4%-78.8%的 Cd 积累在预处理-Se 水稻细胞的细胞壁上。添加 Se 增加了细胞壁的木质素含量和厚度，通过原子力显微镜（AFM）确定，这导致细胞壁的机械力得到改善。此外，Se 预处理降低了参与 Cd 摄取（OsNramp5）和运输（OsLCT1）的基因的表达，但激活了参与 Cd 向液泡运输（OsHMA3）和木质素合成（OsPAL、OsCoMT 和 Os4CL3）的基因的表达。这些结果表明，供应 Se 通过调节木质素合成和 Cd 相关基因的表达来减轻 Cd 毒性。本研究结果为 Se 降低水稻 Cd 吸收的可能解释提供了新的见解。
