ABSTRACT
Glycogen synthase kinase 3/SHAGGY-like kinase (GSK3) proteins play important roles in regulating plant growth, development, and stress response. In order to reveal the characteristics of GSK family members in the medicinal plant Senna tora L., in this study, we conducted the identification and expression analyses of GSKs in S. tora based on its whole genome data, combined with bioinformatics and gene expression research methods. The results showed that a total of nine S. tora GSK genes were identified, all of which contained the GSK characteristic kinase domains. All members were distributed on six chromosomes, the encoding amino acid length ranged from 465 to 943 aa, the protein molecular weight was from 33.57 to 88.83 kDa, and the average isoelectric point was 8.2. The StoSKs were divided into four evolutionary branches, and the StoSKs in the same evolutionary branch shared the same exon/intron structure and conserved motifs. The expansion of the StoSKs gene family was mainly due to segment duplication events, and there were 17, 11, 8 and 7 pairs of collinear genes with Glycine max, Medicago truncatula, Arabidopsis thaliana and Oryza sativa, respectively. The promoter regions of StoSKs mostly contained responses elements related to stress stimulation, growth and development, and hormone induction. Transcriptome data analysis showed that StoSKs were expressed in different tissues, with the highest expression level in roots. Quantitative real-time PCR (qRT-PCR) analysis indicated that StoSKs in different evolutionary branches displayed a synergistic expression pattern response to light, and most of StoSKs could rapidly respond to NaCl stress with significantly up-regulated expression. All the results provide a basis for further analysis of the biological functions of the GSKs gene family in S. tora.