Cloning And Salt-resistant Functional Analysis Of LpNAC17 Gene From Lilium Pumilum

Lilium pumilum is a perennial wild herb of liliaceae,which has ornamental,edible and medicinal value.It is an excellent wild germplasm resource because of its wide distribution and strong resistance.The NAC family of transcription factors is unique to higher plants.It plays an important role in the regulation of plant growth and development,and is also involved in the response of plants to biotic and abiotic stresses.In this study,LpNAC17 gene was cloned from Lilium pumilum and its sequence was analyzed by bioinformatics;The temporal and spatial expression of LpNAC17 gene in different tissues under different stress conditions was quantitatively analyzed by fluorescence real-time;Over-expression vector was constructed to transform tobacco by Agrobacterium-mediated transformation;The salt resistance function of LpNAC17 gene was clarified by testing resistance of transgenic tobacco.This study laid a foundation for the molecular mechanism of antistress in Lilium pumilum,and provided a theoretical basis for the functional analysis of NAC transcription factors.The main research results are as follows:1.The LpNAC17 gene was cloned from Lilium pumilum with a total length of 507 bp,encoding 168 amino acids and belonging to the NAC gene family.The highest homology between this gene and Cinnamomum micranthum was 91.1%.Phylogenetic tree results showed that this gene was most closely related to Phoenix dactylifera and Prosopis alba.The LpNAC17 gene was expressed in all tissues of Lilium pumilum and is sensitive to salt and low temperature under abiotic stress.2.Plant over-expression vector pBI121-LpNAC17-GFP was constructed.Through genetic transformation,screening and verification,five transgenic tobacco strains with LpNAC17 gene were obtained.3.Under salt stress,root length and fresh weight growth of control tobacco seedlings were significantly inhibited compared with transgenic tobacco seedlings.Photosynthesis of transgenic tobacco wine was stronger than that of control.The content of MDA,O2-and H2O2 in transgenic tobacco with LpNAC17 gene was significantly wer than that of control.The content of chlorophyll-proline and the activity of antioxidant enzyme(POD,SOD and CAT)in LpNAC17 transgenic tobacco were significantly higher than those in control.Under salt stress,the expression of stress related genes of CsSOD,CsPOD,CsCAT,HAK,PMA4 and SOS1 in transgenic tobacco were up-regulated,and the expression level of transgenic tobacco was higher than that of control.