Abstract:

In plants, betaine is synthesized upon abiotic stress, in which phosphoethanolamine N-methyltransferase（PEAMT）and choline monooxygenase (CMO) are key enzymes. A plant expression vector pYLTAC747N-Mar-SePEAMT-SeCOM-Mar, which includes SePEAMT gene and SeCMO gene cloned from Salicornia europaea, and the matrix attachment region (Mar) isolated from tobacco, was obtained based on Cre/LoxP recombination system. The resultant plasmid was transferred into Agrobacterium tumefaciens EHA105 by the electroporation method, then transferred into tobacco (Nictiana tabacum L. cv. 89) via Agrobacterium-mediated method. PCR analysis showed that genes were transformed successfully into the transgenic plants. In the condition of NaCl stress for 35d, the transgenic plants could root while the wild-type plants could not. The glycine betaine content of transgenic plants was significantly higher than wild type plants, and the glycine betaine content of transgenic plants was about 5.6~7.7 fold of wild plants. Transgenic plants exhibit significantly lower relative conductivity and higher content of chlorophyll. The data suggest that co-expression of SePEAMT and SeCMO might increase the glycine betaine content and improve the salinity tolerance of engineered plants.