Study Of Heavy Metal Tolerance Of Lea Gene And Cotransformation Of Lea And EIF5A Into Populus Davidiana Dode × P.bollena Lauche

Both Lea and eIF5A are involved in stress tolerance. We had cloned these two genes from Tamarix plants. In the present study, we investigated the heavy metal tolerance of Lea, and cotransformation of these two genes into Populus davidiana Dode×P. bollena Lauche. We determined the time course expression of Lea in Tamrix in response to different heavy metal stress using real time RT-PCR. The results showed that the Lea gene can be differentially regulated by the treatments of NaCl, ZnCl2, CdCl2 and CUSO4.Subcelluar location analysis showed that the LEA is targeted to cytoplasm and nuclear.To study the CdCl2 stress tolerance of the Lea, we employed 5 Lea transformed lines of Populus davidiana Dode×P.bollena Lauche (line 1 to 4).Comparison of the growth of Lea transformed lines and WT plants showed that line 1 and 2 grow better than other transgenic lines and WT plants.SOD activity, MDA level, POD activity, and proline content were measured and compared among the transgenic and WT plants.Our results showed that after stress for 7 d, most transgenic lines had a higher activity of SOD and POD, higher level of proline; while MDA content in transgenic lines was lower than WT plants. These results indicated that Lea may confer stress tolerance by improving the ability of ROS scavenging, elevated the level of proline and soluble proteins.The genes of Lea and eIF5A were inserted into plant expression vector pROKII under 35 S CAMV promoter, respectively. These two genes were transformed into P. davidiana×P. bollena Lauche using Agrobacterium-mediated method.In total,14 kanamycin resistant lines were obtained, and were further confirmed by PCR detection. We randomly selected 7 lines for Northern detection analysis; the results showed that the Lea and eIF5A were successfully expressed in transgenic plants. Salt and osmotic tolerance test were performed by planting the transgenic and WT plants in cultured medium supplied with NaCl and Sorbitol.The results showed that the transgenic plants showed improved salt and osmotic tolerance compared with WT plants.