Abstract:

【Objective】Cloning and characterization of tobacco NAC transcription factor gene could provide a foundation for studying its function and relationship between the root development and nicotine biosynthesis after tobacco topping. 【Method】The full-length cDNA sequence of NtNAC-R1 was amplified by in silico cloning and RT-PCR, and was expressed in Escherichia coli BL21. The expression pattern of NtNAC-R1 in root before and after tobacco topping was analyzed by RT-PCR and Northern blotting. 【Result】NtNAC-R1 had an 936 bp open reading frame in length, encoding 311 amino acids, with a typical conserved domain of NAC transcription factor family. Phylogenetic analysis showed that NtNAC-R1 had the highest homology with the NAC domain in Petunia and belonged to special NAC family in Solanaceae. This novel gene showed expression activity in prokaryotic cells. NtNAC-R1 had a highest expression level in root, with a decreased expression level at 2 h and 4 h after topping, then rose.【Conclusion】NtNAC-R1 was isolated from tobacco root, and it showed higher transcript levels in the roots, and significantly decreased after 2-4 h of tobacco topping, indicating the NtNAC-R1 can play an important role in the signal transduction of tobacco topping.

Key words: tobacco (Nicotiana tabacum L.), NAC transcription factor, RT-PCR, Northern blotting, tissue expression