Dhankher Om Parkash, Shasti Nupur A, Rosen Barry P, Fuhrmann Mark, Meagher Richard B
Department of Genetics, University of Georgia, Athens, GA 30602, USA.
Department of Biochemistry and Molecular Biology, Wayne State University, Detroit, MI 48201, USA.
New Phytol. 2003 Aug;159(2):431-441. doi: 10.1046/j.1469-8137.2003.00827.x.
• Cadmium (Cd) is a major environmental pollutant that poses a serious threat to natural ecosystems. However, most initial attempts to engineer phytoremediation of Cd have not succeeded in developing sufficient Cd tolerance for vigorous plant growth. • We found that the bacterial arsenate reductase gene (arsC) provided Cd(II) resistance to Escherichia coli. When ArsC is overexpressed in tobacco (Nicotiana tabacum) and Arabidopsis thaliana, both transgenic plant species showed significantly greater Cd tolerance than wild-type controls. • At 50, 75, and 100 µm concentrations of Cd (II), the ArsC expressing transgenic lines grew bigger with broader leaves and longer roots than wild-type controls, which were stunted, turned yellow, flowered early, and often died. At the various Cd(II) concentrations, ArsC transgenic plants attained f. wt 2-3-fold higher than the wild-type plants and had roots significantly longer than wild-type plants. These transgenic plants also contained 30-50% higher Cd concentrations than wild-type plants. • It is likely that the arsC gene directs Cd tolerance via the electrochemical reduction of Cd(II) to Cd(0).
• 镉（Cd）是一种主要的环境污染物，对自然生态系统构成严重威胁。然而，大多数最初尝试利用植物修复镉污染的努力都未能成功培育出对镉具有足够耐受性以实现植物茁壮生长的品种。
• 我们发现细菌砷酸盐还原酶基因（arsC）赋予大肠杆菌对Cd（II）的抗性。当ArsC在烟草（Nicotiana tabacum）和拟南芥中过表达时，这两种转基因植物品种均表现出比野生型对照更强的镉耐受性。
• 在Cd（II）浓度为50、75和100µm时，表达ArsC的转基因株系比野生型对照长得更大，叶片更宽，根更长，而野生型对照则生长受阻、变黄、过早开花且常常死亡。在各种Cd（II）浓度下，ArsC转基因植物的鲜重比野生型植物高2至3倍，根也明显比野生型植物长。这些转基因植物的镉含量也比野生型植物高30%至50%。
• arsC基因可能通过将Cd（II）电化学还原为Cd（0）来指导对镉的耐受性。
