NMT历史上的今天丨硒通过调节木质素合成和镉相关基因的表达减少水稻对悬浮细胞的镉吸收

NMT作为生命科学底层核心技术，是建立活体创新科研平台的必备技术。2005年~2020年，NMT已扎根中国15年。2020年，中国NMT销往瑞士苏黎世大学，正式打开欧洲市场。

NMT历史上的今天

2018年07月01日，广东省科学院生态环境研究所李芳柏用NMT发表了标题为Selenium reduces cadmium uptake into rice suspension cells by regulating the expression of lignin synthesis and cadmium-related genes的研究成果。

期刊：Science of The Total Environment

主题：硒通过调节木质素合成和镉相关基因的表达减少水稻对悬浮细胞的镉吸收
标题：Selenium reduces cadmium uptake into rice suspension cells by regulating the expression of lignin synthesis and cadmium-related genes

检测指标：Cd²⁺流速

作者：广东省科学院生态环境研究所李芳柏、崔江虎

英文摘要

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  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 Cd²⁺ influx decreased significantly in the Se-pretreated rice cells in a concentration-dependent manner. The results of inductively coupled plasmamass 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.

中文摘要

尽管以前的研究表明硒可以减少水稻对镉的吸收，但是在细胞水平上的机制尚未见报道。在此，将在有硒或无硒的情况下暴露于Cd处理的水稻悬浮细胞与单独处理相比，用硒进行预处理可使活细胞的比例增加83.1％。硒预处理的水稻细胞中的活性氧水平和线粒体膜电位分别降低了86.6％和76.0％。

此外，非损伤微测技术表明，硒预处理的水稻细胞中Cd²⁺流入量的平均值以浓度依赖的方式显着降低。电感耦合等离子体质谱法（ICP-MS）的结果表明，预处理的Se水稻细胞的细胞壁上积累了67.4％–78.8％的Cd。Se的添加增加了木质素的含量和细胞壁的厚度，从而导致了细胞壁机械力的改善，这是通过原子力显微镜（AFM）确定的。

此外，Se预处理降低了Cd吸收（OsNramp5）和转运（OsLCT1）相关基因的表达，但激活了Cd转运至液泡（OsHMA3）和木质素合成（OsPAL，OsCoMT和Os4CL3）的基因表达。这些结果表明提供硒通过调节木质素合成和Cd相关基因的表达来减轻Cd毒性。目前的发现为对水稻中硒减少的镉吸收的合理解释提供了新的见解。

(A) Representative cell and the Cd²⁺-selective microelectrode; (B) The average Cd²⁺ flux values (mean ± SD) in the rice cells was detected in the absence or presence of Se.