转柽柳金属硫蛋白基因（MT1）烟草的获得及对重金属镉的抗性分析

将柽柳（Tamarix. sp）金属硫蛋白基因（MT1）插入到植物表达载体pBI121，利用农杆菌（Agrobactrium tumefaciens）介导法将MT1导入烟草基因组。对转基因T1植株的卡那霉素抗性分析表明，多数转基因植株后代表现为3:1的分离比例，只有少数转基因植株的抗性分离表现为15:1或不符合孟德尔遗传的分离比例。说明整合到烟草基因组的外源基因多为单拷贝基因，也有少数为多拷贝基因。对具有卡那霉素抗性的转基因植株进行PCR-Southern检测和Northern杂交分析表明，外源MT1基因已整合到烟草基因组，并且得到了正确表达。转基因植株对重金属镉的抗性比对照显著提高，表现为转基因植株的株高和鲜重均明显优于非转基因株系。

Obtainment of Transgenic Tobacco with Metallothionein(MT1 ) Gene from Tamarix sp. and Analysis of Its Tolerance to Cadmium

A metallothionein gene from Tamarix. sp was directionally cloned into the pBI121 binary vector, in place of the XbaI – SacI GUS cassette. The Cauliflower mosaic virus (CaMV) 35S promoter/-nopalin synthase (nos) terminator system and kanamycin resistant gene (NPT II; neomycin phosphotransfers II) were used for these constitutive expression systems. The plasmid was then introduced into Agrobacterium tumefaciens (strain EHA105) by electroporation. Tobacco primary transformants were produced by leaf disc transformation. Kanamycin tolerance analysis showed that most transgenic plants have one copy of the exogenous gene in tobacco transformants. Southern and Northern hybridization indicates that exogenous gene has been integrated into the transgenic tobacco plants, and has been correctly expressed under the control of 35S promoter. Transgenic tobacco plants showed a better tolerant ability to cadmium than that of non- transformant.