Overexpression of an MYB-Related Gene FvMYB1 from Fraxinus velutina Increases Tolerance to Salt Stress in Transgenic Tobacco

MYB transcription factors (TFs) in plants play important roles in abiotic stress tolerance. Here, we report that an MYB-related TF gene, named FvMYB1, was isolated from the salt-tolerant tree species Fraxinus velutina Torr. The real-time PCR analysis showed that the FvMYB1 transcript increased remarkably in response to salt treatment. Subsequently, the FvMYB1 gene was transferred into the tobacco genome via the Agrobacterium-mediated approach. PCR and Southern blot verified that the FvMYB1 gene had been expressed in transgenic tobacco. The overexpressing transgenic seedlings displayed better salt tolerance in root length, shoot fresh weight, and shoot/root ratio compared to the wild type. Moreover, along with the superoxide dismutase and peroxidase activities and proline content that were significantly increased in the transgenic plants, the transcriptions of a series of stress-responsive genes were up-regulated under salt treatment. Further, an analysis of the upstream sequence of the FvMYB1 gene revealed that the promoter could enhance GUS gene expression in transgenic tobacco with NaCl treatment. These results indicate that FvMYB1 functions as a transcriptional activator that plays a regulatory role in salt stress tolerance of F. velutina.