[Identification and expression profiling of SAPK gene family members in Dendrobium officinale]

To investigate the potential roles of stress-activated protein kinase (SAPK) gene family members in Dendrobium officinale, we employed multiple bioinformatics methods to identify the members of this family. The physicochemical properties, chromosomal localization, phylogenetic relationship, gene structure, and cis-acting elements of each D. officinale SAPK (DoSAPK) member were analyzed. In addition, their expression profiles in different tissues and under the low-temperature or salt stress treatment were determined by real-time fluorescence quantitative PCR. The results showed that D. officinale carried eight DoSAPK family members, which belonged to three groups (groups Ⅰ, Ⅱ, and Ⅲ). These genes were located on seven chromosomes, and there were two pairs of genes with replication. The DoSAPK members within the same group had similar gene structures, conserved motifs, and secondary structures. The cis-acting elements in the promoter regions of DoSAPK genes included abundant hormone and stress response elements. DoSAPK family members presented tissue-specific expression in D. officinale. Furthermore, they were differentially expressed under the low-temperature or salt stress treatment, which suggested that they might be involved in the responses to low-temperature and salt stress. Intriguingly, DoSAPK1 might play a role in the abiotic stress responses. The results laid a foundation for in-depth study of the members and roles of the DoSAPK gene family.