Identification and Analysis of Endoplasmic-Reticulum-Stress- and Salt-Stress-Related Genes in Solanum tuberosum Genome: StbZIP60 Undergoes Splicing in Response to Salt Stress and ER Stress

Salt stress can trigger endoplasmic reticulum (ER) stress and affect potato yield. The endomembrane system is tightly regulated in response to salt stress for maintaining cellular homeostasis. However, little is known about the genes involved in the ER-mediated cytoprotective pathways in potato plants. Previously characterized genes involved in the ER stress signaling pathway in Arabidopsis were used as prototypes. We identified 29 genes involved in ER stress response in the potato genome. Transcriptome data analysis showed that the expression levels of related genes were significantly different in different tissues. Most genes can response to β-aminobutyric acid, benzothiadiazole, salt, and mannitol. qRT-PCR assay revealed that they could respond to NaCl and tunicamycin, which was consistent with the fact that the promoter region of related genes contained ER-stress- and abiotic-stress-related cis-elements. Furthermore, we found that StbZIP60 has a splicing form, StbZIP60s, under salt and ER stress, which can be spliced at the CxGxxG site in the C terminus to create a frame shift through the excision of 23 base pairs. StbZIP60 is localized in the cytoplasm and nucleus, whereas most of the StbZIP60s translocated to the nucleus. This study provides a basis for further analyses of the functions of salt-stress- and ER-stress-related genes in potato plants.