• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Experimental Botany >Overexpression of phytochelatin synthase in tobacco: distinctive effects of AtPCS1 and CePCS genes on plant response to cadmium
【24h】

Overexpression of phytochelatin synthase in tobacco: distinctive effects of AtPCS1 and CePCS genes on plant response to cadmium

机译：烟草中植物螯合酶合酶的过表达：AtPCS1和CePCS基因对植物对镉的响应的独特作用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Phytochelatins, heavy-metal-binding polypeptides, are synthesized by phytochelatin synthase (PCS) (EC 2.3.2.15). Previous studies on plants overexpressing PCS genes yielded contrasting phenotypes, ranging from enhanced cadmium tolerance and accumulation to cadmium hypersensitivity. This paper compares the effects of overexpression of AtPCS1 and CePCS in tobacco (Nicotiana tabacum var. Xanthi), and demonstrates how the introduction of single homologous genes affects to a different extent cellular metabolic pathways leading to the opposite of the desired effect. In contrast to WT and CePCS transformants, plants overexpressing AtPCS1 were Cd-hypersensitive although there was no substantial difference in cadmium accumulation between studied lines. Plants exposed to cadmium (5 and 25 μM CdCl2) differed, however, in the concentration of non-protein thiols (NPT). In addition, PCS activity in AtPCS1 transformants was around 5-fold higher than in CePCS and WT plants. AtPCS1 expressing plants displayed a dramatic accumulation of γ-glutamylcysteine and concomitant strong depletion of glutathione. By contrast, in CePCS transformants, a smaller reduction of the level of glutathione was noticed, and a less pronounced change in γ-glutamylcysteine concentration. There was only a moderate and temporary increase in phytochelatin levels due to AtPCS1 and CePCS expression. Marked changes in NPT composition due to AtPCS1 expression led to moderately decreased Cd-detoxification capacity reflected by lower SH:Cd ratios, and to higher oxidative stress (assessed by DAB staining), which possibly explains the increase in Cd-sensitivity. The results indicate that contrasting responses to cadmium of plants overexpressing PCS genes might result from species-dependent differences in the activity of phytochelatin synthase produced by the transgenes.
机译：植物螯合素，一种重金属结合多肽，是通过植物螯合素合酶（PCS）（EC 2.3.2.15）合成的。先前对植物过度表达PCS基因的研究产生了相反的表型，从增强的镉耐受性和积累到镉超敏性不等。本文比较了AtPCS1和CePCS在烟草（Nicotiana tabacum var。Xanthi）中过表达的影响，并证明了单一同源基因的引入如何在不同程度上影响细胞代谢途径，从而导致所需作用的相反。与WT和CePCS转化子相反，过表达AtPCS1的植物对Cd过敏，尽管研究品系之间镉积累没有实质性差异。但是，暴露于镉的植物（5和25μMCdCl 2 ）的非蛋白质硫醇（NPT）浓度不同。此外，AtPCS1转化体中的PCS活性比CePCS和WT植物高约5倍。表达AtPCS1的植物表现出戏剧性的γ-谷氨酰半胱氨酸积累，并伴随着谷胱甘肽的强烈消耗。相比之下，在CePCS转化子中，发现谷胱甘肽水平的降低幅度较小，而γ-谷氨酰半胱氨酸浓度的变化幅度较小。由于AtPCS1和CePCS表达，植物螯合素水平仅有中度和暂时性增加。由于AtPCS1表达引起的NPT组成的明显变化导致SH：Cd比例降低反映了Cd解毒能力的适度降低，以及氧化应激程度较高（通过DAB染色评估），这可能解释了Cd敏感性的增加。结果表明，过表达PCS基因的植物对镉的反差响应可能是由于转基因产生的植物螯合酶合酶活性的物种依赖性差异所致。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号