Cultivated potato (Solanum tuberosum L.) is an important tuber crop in the world. Cold stress adversely affects productivity and quality of potato. However, the molecular mechanism underlying the cold stress responses remains unclear in potato. The chloroplast ultrastructure of S. cardiophyllum in non-acclimated and cold acclimation plants under -2 °C for 6 h contained fewer thylakoid membranes, more spherical than those in 0 h (control, non-acclimated). The chloroplast ultrastructure of S. commersonii in non-acclimated and cold acclimation plants under -2 °C 6 h were similar to the non-cold stress. RNA sequencing (RNA-seq) analysis showed that 3,623 DEGs (differentially expressed genes) were detected in the S. commersonii and S. cardiophyllum with or without cold acclimation. GO analysis revealed that the membrane protein complex, photosynthesis and molecular function regulator were enriched terms in three category of S. commersonii and S. cardiophyllum. KEGG analysis found that genes were enriched to photosynthesis and chlorophyll metabolism. A total of 27 distinct modules were identified by weighted gene co-expression network analysis, four regulatory networks contained cold related genes were constructed. The StMAPK7 were differently expressed in S. cardiophyllum. Subcellular location studies showed that the StMAPK7 protein is mainly localized to the nucleus in tobacco. Overexpression of StMAPK7 exhibited lower electrolyte leakage and less leaves injury area than that of wild type, indicating StMAPK7 positively regulates cold stress in potato. These findings would provide fundamental insight into the cold stress response regulatory networks and supply a theoretical basis for breeding cold-resistant potato cultivars.