Cloning Of NAC Transcriptional Factors Based On Transcriptome In Bambusa Emeiensis And Its Genetic Transformation

The growth and development of plant will be affected by the biotic stress and abiotic stress, such as drought and cold stress. In order to avoid these factors on the growth and development of plant, plants have corresponding mechanisms, including the activation and expression of genes associated with the stress, such as the transcription factors WRKY, NAC, MYB and bZIP. The four NAC genes in Bambusa emeiensis were cloned based on the transcriptome database of shoots in Bambusa emeiensis. The bioinformatics, tissue expression patterns, stress-induced expression analysis, transcriptional activity, and transformation into Populus cathayana Rehd were performed. It provides a theoretical basis for improving bamboo by transgenic engineering. The main results are as follows:The full-length sequences of four BeNAC gene in Bambusa emeiensis were cloned based on the transcriptome database of shoots in Bambusa emeiensis. They were named BeNAC1, BeNAC2, BeNAC3 BeNAC4, respectively. The full-length cDNA sequence of BeNAC1, BeNAC2, BeNAC3 BeNAC4 were 939 bp, 1167 bp,1953bp, 1539 bp, and encoded 313, 389, 651 and 513 amino acids, respectively. Their accession numbers in GenBank were KU550706, KU821586, KU821587 and KU821588, respectively. The proteins encoded by BeNAC genes were hydrophilic. In their secondary structures, random coil was more than ?-helix and extended strand,while ?-turn was the least.The results of transcriptional activity analysis on four NAC transcription factors from Bambusa emeiensis showed that the strong transcriptional activity was found in the transcription factor BeNAC3 and BeNAC4, but BeNAC1 and BeNAC2 were no transcriptional activity.The tissue expression patterns of four BeNAC genes were analyzed by the technique of real-time PCR. The results showed that four BeNAC gene sequences were expressed in all shoots, stems, unfolding leaves and rolled leaves of Bambusa emeiensis. Meanwhile, in BeNAC1 and BeNAC2, the expression level of stem was more than that of unfolding leaves and shoots, while the expression level of rolledleaves was the least. In BeNAC3 and BeNAC4, the expression level of shoots was more than that of unfolding leaves and rolled leaves, while the expression level of stem was the least.The seedlings in Bambusa emeiensis were treated with ABA(200 ?mol ? L-1),NaCl(200 mmol ? L-1) and PEG 6000(20%) stress. The stress-induced expression in BeNAC2, BeNAC3 and BeNAC4 gene was analyzed by Real-time PCR technology.The results showed that the expression level of BeNAC2 and BeNAC4 genes treated by salt, drought and ABA stress was higher than that of BeNAC3.A preliminary deduction is that the expression of BeNAC2 and BeNAC4 genes could be related to the abiotic stress.pCAMBIA 1303-BeNAC2-4 overexpression vectors were successfully constructed. Then the pCAMBIA 1303-BeNAC3 vector was transformed into Populus cathayana by Agrobacterium-mediated. The transgenic Populus cathayana plant was obtained, which laid a foundation for functional research of BeNAC3 gene in the future.