表达长喙田菁SrPCS4烟草的获得及Cd抗性研究

植物螯合肽(phytochelatins,PCs)在植物解除重金属的毒性方面具有重要作用,是以谷胱甘肽为底物,在植物螯肽合成酶(phytochelatin synthase,PCS)催化下合成的.作者已经克隆得到的长喙田菁(Sesba-nia rostrata)植物螯合肽合成酶SrPCS4 cDNA长为1035 bp,其ORF编码177个氨基酸,以pHANNIBAL及pART27为基础,构建了CaMV35S启动子驱动的SrPCS4基因植物表达载体pAM25,采用电击转化方法将pAM25导入根癌农杆菌EHA105,并通过改良叶盘转化方法用该菌株对烟草进行了转化,对转基因烟草进行了PCR与northern-blot检测,研究结果表明得到了表达该基因的烟草,但表达该基因的烟草不能够提高对Cd的抗性.

Study on Preparation and Cadmium Resistance of Transgenic Tobacco of Sesbania rostrata Phytochelatin Synthase4

Phytochelatins(PCs) post-translationally synthesized directly from glutathione(GSH) by the enzyme phytochelatin synthase(PCS) play an important role in heavy metals detoxification in plants.The phytochelatin synthase(SrPCS4) cDNA full-length obtained from Sesbania rostrata was 1035 bp and contained open reading frame encoding 177 amino-acids.Phylogenetic analysis with ClustalW indicated that SrPCS4 exhibited high homologous with PCS from legume.Then the CaMV35S promoter driving plant expression vector pAM25 with SrPCS4 was constructed based on the pHANNIBAL and pART27.By electroporation transformation,pAM25 was transferred into Agrobacterium tumefacien EHA105 and the new engineering bacterium was transferred into Nicotiana tabacum by the modified leaf-disc method.Transgenic tobacco expressed SrPCS4 was identified by northern-blot,but the transgenic tobacco could not enhance cadmium resistance.