龙葵SorMT2a和SorMT2c基因的克隆及其转化烟草研究

Cloning of SorMT2a and SorMT2c from Solanum nigrum and Study on Their Transformation to Nicotiana tobacum

以龙葵为试验材料,利用RT-PCR技术分离到2个长度不同的编码Ⅱ类MT(金属硫蛋白)的cDNA克隆SorMT2a(EU760481)和SorMT2c(EU760483),成功构建植物表达载体pROKⅡ-SorMT2a和pROKⅡ-SorMT2c,通过农杆菌介导法转化烟草并通过PCR验证了基因的表达情况。与野生植株相比,转SorMT2a和SorMT2c基因烟草对镉的耐受性不同,有的转SorMT2a基因植株在MS培养基中的CdCl2浓度达到200μmol/L时仍然生长良好,生物量和株高均大于野生型植株;而转SorMT2c基因植株对镉的耐受性没有提高。这说明SorMT2a基因在植物对镉的耐受性中起作用,而SorMT2c基因则不起作用,从而也说明了同一类基因不同家族可能具有不同功能。

From Solanum nigrum L.,SorMT2a（EU760481）and SorMT2c（EU760483）with different number of nucleotides and encoding type Ⅱmetallothionein were isolated by RT-PCR.The plant expression vectors pROKⅡ-SorMT2a and pROKⅡ-SorMT2c were successfully constructed and transformed to the tobacco（Nicotiana tobacum） by Agrobacterium mediation and the transgenic seedlings were verified by PCR.The experiment on Cd tolerance indicated that transgenic plants of SorMT2a and SorMT2c had different tolerance to Cd.Compared with wild seedlings,most of the transgenic seedlings of SorMT2a could grow well in the MS medium supplemented with 200 μmol/L CdCl2 with larger biomass and greater plant height,while the Cd tolerance of transgenic seedlings of SorMT2c was not enhanced.From these results,the conclusion could be made that SorMT2a played a role in the Cd tolerance while SorMT2c did not have this function,which might suggest that different families of the MTs have different functions.