Functional Confirmation Of MT Gene From Tamarix Sp. And Obtainment Of Transgenic P.davidiana×P.bolleana With MT Gene

A metallothionein gene(MT1) 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. PCR-Southern blot and Northern blot indicates that exogenous gene has been integrated into the transgenic tobacco plants, and has been correctly expressed under the control of 35S promoter.The growth and physiologic Characters of transgenic tobacco and non-transformant for CdCl2 and NaCl tolerance was studied. The results showed that: under different CdCl2 and NaCl concentration, the activity of POD,SOD and concentration of chlorophyll was increased, whereas the activity of MDA was decreased. Enhanced growth of transgenic tobaccos was observed at the early development stages, resulting in plant height and fresh weight significant greater than those of non-transformant. These results demonstrate that the exogenous methallothionein expression increased the ability of cleaning up active oxygen than that of non-transformant, so it has a stronger tolerance to CdCl2 and NaCl stress.The metallothionein(MT1) also was transferred into P. davidiana×P. bolleana by the same way with Tobacco.