Identification and characterization of the bZIP transcription factor family and its expression in response to abiotic stresses in sesame.

Basic leucine zipper (bZIP) gene family is one of the largest transcription factor families in plants, and members of this family play important roles in multiple biological processes such as light signaling, seed maturation, flower development as well as abiotic and biotic stress responses. Nonetheless, genome-wide comprehensive analysis of the bZIP family is lacking in the important oil crop sesame. In the present study, 63 bZIP genes distributed on 14 linkage groups were identified in sesame, and denominated as SibZIP01-SibZIP63. Besides, all members of SibZIP family were divided into nine groups based on the phylogenetic relationship of Arabidopsis bZIPs, which was further supported by the analysis of their conserved motifs and gene structures. Promoter analysis showed that all SibZIP genes harbor cis-elements related to stress responsiveness in their promoter regions. Expression analyses of SibZIP genes based on transcriptome data showed that these genes have different expression patterns in different tissues. Additionally, we showed that a majority of SibZIPs (85.71%) exhibited significant transcriptional changes in responses to abiotic stresses, including drought, waterlogging, osmotic, salt, and cold, suggesting that SibZIPs may play a cardinal role in the regulation of stress responses in sesame. Together, these results provide new insights into stress-responsive SibZIP genes and pave the way for future studies of SibZIPs-mediated abiotic stress response in sesame.