| Spartina alterniflora is one of the most important invasive species in China’s coastal salt marsh system in recent years,largely due to its strong salt tolerance.Transcription factors are one of the key factors regulating the response of plant salt stress.Therefore,to study whether the S.alterniflora transcription factor can be used for salt tolerance improvement of agricultural and forestry plants,transcription factors were identified using bioinformatics methods from the full-length transcriptome and RNA-seq of S.altemiflora under different salt stress conditions.In addition,the SaNAC48 encoding genes were cloned and the bioinformatics analysis,tobacco subcellular localization and yeast transcriptional activation activity of SaNAC48 were systematically carried out.The SaNAC48 gene was overexpressed into model plantArabidopsis,and subjected to a functional analysis of salt stress response using homozygous transgenic lines.The main results of this study are as follows:(1)Bioinformatics analysis shows that there are 1338 transcription factors of S.alterniflora,which are derived from 52 families of transcription factors,covering 90%of plant transcription factor families.The most abundant TF families include bHLH,bZIP,NAC,MYB,WRKY,ERF and other families.Preliminary results indicate that there are a large number of transcription factors in S.alterniflora.(2)Analysis of transcriptome data showed that 242 transcription factors in S.alterniflora had different gene expression under different salt stress,and 65%of transcription factor gene expression was positively correlated with salt stress.These transcription factors belong to 38 families,most of which are derived from the NAC,ERF,WRKY,bZIP,bHLH and MYB families.In-depth study found that 18 transcription factors sustained differential expression at different salt concentrations,indicating that the above transcription factors may have important functions in response to salt stress.(3)Bioinformatics analysis showed that SaNAC48 has a conserved NAC domain.The homologous evolutionary analysis found that SaNAC48 is similar to gramineous crop such as sorghum,maize,sugarcane,rice,etc.,indicating that SaNAC48 has similar functions to monocot NAC48.(4)Subcellular localization of tobacco leaves and yeast transcriptional activation activity showed that SaNAC48 is localized in the nucleus and SaNAC48 has transcriptional activation activity,thus confirming that SaNAC48 acts as a transcription factor.(5)Over-expression of SaNAC48 into Arabidopsis thaliana showed that the roots of SaNAC48 overexpressing lines were significantly longer than the control group under high salt stress;the senescence of leaves from SaNAC48 overexpressing transgenic lines were delayed under high salt treatment compared with the control group,indicating SaNAC48 can improve the salt tolerance of plants.In summary,S.alterniflora has many usefull salt stress response transcription factors,and transcription factors such as SaNAC48 have the potential to provide genetic resources for salt tolerance improvement of agricultural and forestry plants. |
