Transcriptome Profiling of the Salt-Stress Response in Paper Mulberry

Paper mulberry is a high-quality woody feed resource plant with high crude protein content. It is widely distributed in China and has excellent characteristics of salt and alkali tolerance. Paper mulberry has ecological and economic importance. Salt stress has become a critical factor with the increasing degree of soil salinity that restricts plant growth. In the saline-alkali environments, transcriptome expression is altered leading to phenotypic defects in most plants. However, the regulatory mechanism related to paper mulberry's salt-stress (SS) response is not clearly understood. In the present study de novo transcriptomic assembly was performed, and gene expression levels were measured between different SS and natural conditions (25 degrees C) as a control for paper mulberry plants. According to the results of our study, under NaCl stress conditions, the differential gene expression was observed in the leaves of paper mulberry compared with the control. A total of 2126 differentially expressed unigenes were observed. Among these unigenes the expression of 812 DEGs was up-regulated and the expression of 1,314 DEGs was down-regulated. Additionally, The GO and KEGG analyses regarding differentially expressed unigenes (DEUs) revealed that the observed critical transcriptomic alterations under salt stress (SS) conditions were associated with primary and secondary metabolism, photosynthesis, and plant hormone signaling pathways. Further investigations such as gene function studies regarding the unigenes depicting altered expression under salt stress conditions in paper mulberry will help understand the mechanism of salt tolerance, and this information can be utilized in paper mulberry breeding and improvement programs.