Abstract：Choline monooxygenase (CMO) is an important rate-limiting enzyme in the biosynthesis of betaine. To investigate the application that transform cmo gene in Salicornia bigelovii to the Nicotiana tabacum, basic plasmid pCAMBIA1300UR was used to construct the expression vector pCAMBIA1300UR-cmo. Then the reconstructed expression vector was mediated into agrobacterium EHA105 by electric shock. So that the recombinant vector were introduced into the tobacco genome by Agrobacterium tumefaciens mediated transformation. Antibiotics (kanamycin) screening, PCR and qRT-PCR were all used to confirm the success of transformation. After treated with different concentrative NaCl for 10 d, the transgenic tobacco was searched for the evidence of salt tolerance. The results showed that the transformative efficiency of cmo were estimated up to 80%. When treated by the condition of 200 mmol/L of NaCl, the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and proline (PRO) of transgenic tobacco were stronger obviously than that in the non-transgenic plants except the content of MDA and H2O2. So the cmo gene could improve the salt tolerance in the tobacco plants. The study laid the foundation of finding and exploitation of resistant genes from stress-tolerant plants.
