The transcriptional regulatory network of hormones and genes under salt stress in tomato (Solanum lycopersicum L.)

Salt stress has become one of the main limiting factors affecting the normal growth and development of tomato as well as fruit quality and yield. It is of great significance to clarify the physiological metabolism law and salt tolerance mechanism of tomato under salt stress. Through physiological and photosynthetic indicators, salt stress can stimulate the production of protective enzymes, induce stomatal closure and reduce the photosynthetic rate. To further reveal the regulatory relationship of tomato hormones under salt stress, the interaction between hormones and TF and the genome-wide gene interaction network, abscisic acid (ABA), jasmonic acid (JA), cytokinin (tZ), salicylic acid (SA), auxin (IAA), and gibberellin (GA) levels were quantified. The samples were then sequenced by RNA-seq and analyzed at different time points after NaCl treatment. After NaCl treatment, the levels of ABA, SA and JA were significantly increased, the levels of GA were decreased, and IAA and tZ showed a trend of first increasing and then decreasing. The expression patterns of hormone biosynthesis and signal transduction-related genes were analyzed based on transcriptome expression profiling, the coexpression network of hormones and genome-wide coexpression networks were constructed using weighted gene coexpression network analysis (WGCNA), and the expression patterns of specific transcription factors under salt stress were systematically analyzed, which indicated 20 hormone-related salt tolerance candidate genes. In conclusion, we first revealed the relationship between hormones and genes in tomato under salt stress based on hormone and transcriptome expression profiles, constructed a gene regulatory network, and proposed a transcriptional regulation model of tomato salt tolerance, which consists of six types of hormones. A total of 14 transcription factor-like (TFs) and 52 coregulated target genes laid the foundation for further analysis of the molecular mechanism and regulatory network of tomato salt tolerance.