Enhanced Cadmium Accumulation in Transgenic Tobacco Expressing the Phytochelatin Synthase Gene of Cynodon dactylon L

Bermudagrass (L 上的 Cynodon 扬抑抑格。cv。Goldensun ) 对高度抵抗并且积累大量镉(Cd ) 。phytochelatin synthase (PCS ) cDNA (CdPCSI ) 被 cDNA 结束的快速的扩大从这棵草孤立。通常认为的 CdPCSI 蛋白质从另外的植物与 PCS 分享了高相同，与在 N 终端的 79% 相同和在 theC 终端的 47% 相同。然而， 16 Cys 残余在 CdPCS1 的 C 终端被发现，并且在这些残余之中，三个位置与另外的 PCS 蛋白质不同。Semiquantitative reversetranscription 聚合酶链反应分析证明 Cd 应力在 Bermudagrass 在根和叶子导致了 CdPCSI 表示。我们证实 CdPCSI 由在 ABDE1 表示基因在酵母房间在 Cdtolerance 起一个重要作用， Cd 敏感的异种。CdPCSI 然后被介绍进烟草植物。在某转基因的烟草的 phytochelatin 水平在野生型植物非常衬里 increased3.88 褶层，在这些转基因的植物的 Cd 累积因此是 enhanced3.21 褶层。结果建议 CdPCSI 以后能为植物救治被用作一个基因要素。

Bermudagrass （Cynodon dactylon L. cv. Goldensun） is highly resistant to and accumulates large amounts of cadmium （Cd）. A phytochelatin synthase （PCS） cDNA （CdPCS1） was isolated from this grass by rapid amplification of cDNA ends. The putative CdPCS1 protein shared a high homology with PCS from other plants, with 79% homology at the N-terminal and 47% homology at the C-terminah However, 16 Cys residues were found at the C-terminal of CdPCS1, and among these residues, three positions were different from other PCS proteins. Semiquantitative reverse transcription-polymerase chain reaction analysis showed that Cd stress induced CdPCS1 expression in both roots and leaves in Bermudagrass. We verified that CdPCS1 plays an important role in Cd tolerance in yeast cells by expressing the gene in ABDE1, a Cdsensitive mutant. CdPCS1 was then introduced into tobacco plants. The phytochelatin level in some transgenic tobacco lines increased 3.88-fold more than in wild type plants and Cd accumulation in these transgenic plants was enhanced 3.21-fold accordingly. The results suggested that CdPCS1 could be used as a gene element for phytoremediation in the future.