| Populus simonii × P.nigra is an important greening and afforestation tree species in the East and west north areas.It has the characteristics of fast growth and high yield,strong adaptability and so on.NAC transcription factor is a unique transcription factor family of plants,which plays an important role in plant growth and development and resisting external stress.In this study,taking P.simonii × P.nigra as material,the salt stress tolerance function of transcription factor PsnNAC054 was analyzed.The results are as follows:(1)A 1080 bp cDNA fragment of the coding region of PsnNAC054 gene was cloned from P.simonii × P.nigra,which encodes a protein containing 359 amino acid residues;The protein belonged to unstable basic hydrophilic protein and did not contain transmembrane structure.There was a conserved domain composed of 134 amino acids at its N-terminal;It was closely related to NAC protein of Populus trichocarpa and Populus deltoide.(2)PsnNAC054 protein was located in the nucleus and had transcriptional activation activity.The transcriptional activation region was located in 149 amino acids at the C-terminal of the gene.PsnNAC054 gene expression had tissue-specificity,and the expression level was the highest in roots;It could be induced by salt stress,and the expression pattern was first upregulated and then down regulated in leaves,stems and roots.(3)Transgenic tobacco and P.simonii × P.nigra overexpressing PsnNAC054 were cultivated.Under salt stress,the growth state of transgenic tobacco and P.simonii × P.nigra were better than that of wild type;the activities of SOD and POD,the contents of proline and chlorophyll were significantly higher than those of wild type,and the content of MDA was lower than that of wild type;by DAB,NBT and Evans blue histochemical staining,the color was lighter than that of the wild type.In conclusion,PsnNAC054 gene was induced to express by salt stress,and overexpression of this gene in plants can improve plant growth and development and enhance its salt tolerance.This paper analyzed the basic structure and function under salt stress of PsnNAC054 gene in Populus simonii × P.nigra,which provided a theoretical basis for studying the resistance mechanism of PsnNAC054 gene under salt stress,and provided gene resources for improving plant resistance. |
