Cloning And Characterization Of Salt Tolerance Genes BetA And Na~+/H~+ Antiporter Of Marinobacter Sp. Verification

Saline-alkali soil is one of the important land resources,especially in the northeast part of China.It occupies a large proportion of uncultivated land resources.The large excess of soluble salt solution in the soil could lead to the different osmotic pressure among plant and environment,which could cause different levels of dehydration and even death of plants.We got a strain of moderate salt tolerant bacteria isolated from Jilantai salt lake of Inner Mongolia Province in China.It was identified as a new species in genus Marinobacter by biological characters and 16 S rDNA sequence.The optimum salting strength is 10%~12%(m/V).The whole genomic sequences were sequenced.In order to identify and characterize the biological functions of salt tolerant related genes in Marinobacter sp.,the following experments were conducted: First,We we search the secquence of betA and Nha in E.coli the putative salt tolerance genes were cloned by homology-based cloning including choline dehydrogenase(betA)and Na~+/H~+ antiporter(Nha)genes.Second,they were constructed to over expression vectors under the drive of CaMV35 S promoter;Then the vectors were transformed to the wild type Arabidopsis thaliana by the method of Agrobacterium infection.The transformed Arabidopsis thaliana were treated with 50~200mM NaCl soulution.The transformed plants showed enhanced salt tolerance comparing to the untransformants.