Abstract: We analyzed the salt tolerance of tobacco plants which expressed both PsATX and PsSOD genes of Polygonum sibiricum Laxm., constructed univalent expression vector pROKⅡ-PsATX, pROKⅡ-PsSOD and dual-gene expression vector pROKⅡ-PsATX-PsSOD respectively, and then transferred them into tobacco mediated by Agrobacterium tumefaciens. The transgenic tobacco were identified by PCR method. We measured the content of malondialdehyde(MDA), reactive oxygen, proline(Pro), and the activity of superoxide dismutase(SOD) in the transgenic tobacco under salt stress condition to identify the salt tolerance of these plants. The transgenic tobacco containing PsATX, PsSOD and PsATX+PsSOD genes respectively were obtained successfully. The integration of the foreign PsATX and PsSOD genes were confirmed by molecular identification. Under the treatment of 100 mmol·L^-1 NaCl solution, the content of MDA, reactive oxygen and proline in the co-transformed plants was lower than that of wild type and univalent transgenic plants, but the SOD activity were higher than them. By the salt test, the transgenic tobacco contained PsATX+PsSOD genes were more tolerant to salt stress than the transgenic tobacco contained PsATX or PsSOD genes.

Key words: PsATX, PsSOD, dual-gene expression vector, salt tolerance