Overexpression of AtNHX5Increases Salt Tolerance of Arabidopsis thaliana

To investigate the role of AtNHX5in plant salt resistance,the plant expression vector pROKⅡAtNHX5was constructed and introduced into Arabidopsis thaliana.RT-PCR assay showed that :(1) AtNHX5was over-expressed in the transgenic lines.(2) Several transgenic homozygous lines and wild-type plants were evaluated for salt stress tolerance,the results suggest that AtNHX5transgenic plants were more tolerant to high NaCl concentrations during germination and seedling stages when compared with wild-type plants.Under saline conditions,both fresh and dry weights of the transgenics as well as Na+ and K+ contents were much higher than that of wild-type.To take transgenic plant a1-4as an example,the shoot fresh weight,dry weight and K+ content were 1.27,1.54and 1.16fold,respectively compared with wild types under 200 mmol/L NaCl treatment,which were significantly higher than that in wild types.These results demonstrate that overexpression of AtNHX5in Arabidopsis promoted the absorbing capacity of K+ and enhanced the salt tolerance of plants.