Selection And Functional Analysis Of Poplar NAC Transcription Factor Gene In Response To Salt Stress

NAC transcription factor family plays an important role in plant growth and development, and in response to abiotic stress. In the presente study, a total of 125 NAC salt-stress responsive genes were screened form 170 NAC transcription factor genes in Populus simonii x P. nigrainby RT-qPCR. PtrNAC15 gene was down regulated under salt stress and differental expreesed in different tissues, which expressed specificity and significantly in the secondary xylem.The cDNA fragment of PtrNAC15 gene was cloned, and plant expression vector was constructed. Transgenic tobacco lines were cultured through Agrobacterium-mediated leaf disc method. Transgenic tobacco over expressing PtrNAC15 gene showed significant increases of germination rate, fresh weight, root length, dry weight, hemicellulose content, lignin content cellulose content and genes expression level of wood formation related when compared to control tobacco. Wood prime genes associated with cellulose expression of transgenic tobacco plants. Phloroglucinol staining results showed that the secondary wall of transgenic tobacco is thickening. The plant expression vector of GUS gene driven by PtrNAC15 gene promoter was constructed and transfered into tobacco genome by agrobacterium. GUS staining indicated that GUS gene expressed in root, stem and leave, mainly expressed in the stem, which were consistent with the results of organizational characteristics.