Cloning And Functional Analysis Of 3 NACs From Caragana Intermedia

The plants that growing in natural environment are usually forced to face various abiotic and biotic stresses.Plants have formed relatively stable mechanism to adapt to stresses during the long-term evolution.NAC transcription factor family is the plant-specific and one of the largest transcription families,and it is involved in plants growth,development and stress responses.Caragana intermedia belongs to Caragana fabr,Leguminosae,which is a kind of shrub species widely distributed in the northwest of China with strong tolerance to drought,cold and saline.In this study,three genes encoding NAC transcription factors were cloned,and their functions were identified primarily.The results are as following:1.CiNAC071 was cloned,and its ORF was 1 017 bp,encoding 339 amino acids.Its promoter sequence was 2 108 bp obtained by PCR amplification.The CiNAC071 promoter has many ABA,MeJA,GA and low-temperature responsive cis-elements.The GUS reporter activity driven by this promoter was mainly concentrated in cotyledon veins,new leaves,hypocotyl and calyces.The CiNAC071 promoter is ABA-and GA-inducible,it was inhibited by ABA but induced by GA treatment.CiNAC071 transgenic Arabidopsis thaliana was more sensitive to salt than wild type under salt treatment,and the salt-responsive genes were down-regulated in the CiNAC071 transgenic lines.It indicates that CiNAC071 enhances plants salt sensitivity by down-regulating the expression of genes involved in salt stress pathway.2.CiNAC038 was cloned,and its ORF was 1 032 bp,encoding 344 amino acids.The expression of CiNAC038 reaches the highest in stem of C.intermedia.Its promoter sequence was 1 800 bp obtained by PCR amplification,and had many cis-elements,such as ABA,MeJA,GA,anaerobic induction,and so on.The GUS reporter activity driven by this promoter was mainly concentrated in the hypocotyl-root junction,root,petals,calyx and anthers of the transgenic A.thaliana,and was ABA-inhibited.3.CiATAF1 was cloned,and its ORF was 873 bp,encoding 291 amino acids.It is mainly expressed in leaf tissue of C.intermedia and was induced by drought,cold and salt.CiATAF1-GFP fusion protein was observed to localize in the nuclei of the protoplast of A.thaliana.