ObjectiveNAC transcription factor is a new kind of transcription factor with many biological functions, which plays an important role in stress response. This paper aims to explore the expression pattern of LpNAC6 gene under stress and its response to salt stress in transgenic tobacco.
MethodLpNAC6 gene from Lilium pumilum was cloned by homologous cloning and analyzed by bioinformatics softwares. Subcellular localization of LpNAC6 protein was performed by particle bombardment. The expression patterns of LpNAC6 gene in different abiotic stresses and different tissues were analyzed by RT-qPCR. The plant expression vector pBI121-LpNAC6-GFP was constructed, and tobacco was transformed for verifying the function of LpNAC6 gene under salt stress.
ResultThe LpNAC6 gene was 909 bp in length and encoded 302 amino acids, it had a highly conserved NAM domain and belongs to the NAC gene family. LpNAC6 protein was a hydrophilic protein with no signal peptide and trans-membrane domain. It had 5 glycosylation sites, 20 phosphorylation sites and subcellular localization of LpNAC6 protein in nucleus. The evolutionary relationship between LpNAC6 gene and NAC transcription factor of Gossypium mustelinum was closest. LpNAC6 gene in L. pumilum responded to ABA, drought, low temperature and salt stress. Under salt stress, the activity of SOD, POD, CAT and the contents of chlorophyll, proline and soluble protein in transgenic tobacco overexpressing LpNAC6 gene were significantly higher than those in wild-type.
ConclusionLpNAC6 gene of L. pumilum can respond to ABA, drought, low temperature and salt stress. Its overexpression can increase the metabolic activity and antioxidant enzyme activity of transgenic tobacco under salt stress, thus enhancing the salt tolerance of tobacco.