Screening And Identification Of Salt Tolerance Function Of SlCXE And SlCYP72A Genes In Sedum Lineare Thunb.

Soil salinization is a major constraint to plant geographical distribution and crop yield.As an excellent ground cover plant,Sedum lineare Thunb.showed strong adaptability under salt stress,but its potential salt resistance mechanism and key salt-tolerant genes were still unclear.In this study,two candidate genes,Sl CYP72A(Cytochrome P450 s 72A,CYP72A)and Sl CXE(Carboxylesterase,CXE),were screened by transcriptome sequencing and transferred into Arabidopsis thaliana for validation of salt tolerance.First,the changes of the roots,leaves and side branches of plant after the treatment with different concentrations of Na Cl were observed and the salt treatment concentration of the transcriptome samples was determined.Then,the de novo transcriptome sequencing was performed on leaf and root samples of Na Cl-treated S.lineare,and 78,407 transcripts and 584 differentially expressed genes were identified in this study.Based on the classification of biological functions,most of the DEGs were classified into processes such as oxidative stress defense,plant hormone regulation and transcription-related processes.Secondly,14 differentially expressed genes were verified by using real-time quantitative techniques in this study.Among them,the expression levels of Sl CYP72 A and Sl CXE genes were increased significantly in the salt-treated roots of S.lineare.Based on the analysis of the biological functions of the plant CXE family and the CYP72 A subfamily,we found that few studies have reported their contribution to plant salt tolerance.Finally,in order to further explore the biological functions of Sl CYP72 A and Sl CXE genes in plant salt tolerance,the Agrobacterium-mediated transgenic technology was used to transfer two candidate genes into the model plant Arabidopsis for functional verification.The results showed that,upon 150 m M Na Cl treatment,35S:Sl CXE but not 35S:Sl CYP72 A transgenic Arabidopsis seedlings exhibited improved salt-resistance as shown by the increased seed germination rates and longer primary roots when compared to wild-type plants.Taken together,this work laid foundation for better understanding of the salt adaptation mechanism of S.lineare and genes identified in this study could serve as useful resources for development of more salt-tolerant varieties of other species through genetic engineering.