PYR/PYL (pyrroloquinoline quinone resistance/PYR1-like) are receptors for abscisic acid (ABA) in plants and play a crucial role in responses to abiotic stress. In this study, we identified 63 members of the StPYL gene family at the tetraploid whole-genome level in potatoes. We analyzed the physicochemical properties of these 63 StPYLs and constructed a phylogenetic tree using Arabidopsis thaliana and potato (Solanum tuberosum L.) cultivar ‘DM’ as the reference. By examining gene structure, conserved protein motifs, and collinearity, we found that StPYLs are highly conserved throughout evolution. The gene expression heat map under salt stress revealed that 57 StPYL genes are involved in the salt stress response. Among them, the expression level of StPYL9a-like changed significantly under salt stress. Through genetic transformation, we observed that overexpression of StPYL9a-like enhanced the growth and survival of potato plants under salt stress compared to the wild type. The contents of proline (Pro), superoxide dismutase (SOD), and chlorophyll in the leaves of overexpressing plants increased, while malondialdehyde (MDA) levels decreased. This suggests that StPYL9a-like positively regulates salt tolerance by affecting antioxidant enzyme activity and osmotic adjustment substances in potatoes. Subcellular localization demonstrated that StPYL9a-like is localized in the nucleus. This study provides a reference for the functional research of PYLs in potatoes, offers a basis for screening potato genes related to salt stress, and lays a foundation for developing salt-tolerant potato varieties.

As the fourth-largest global food crop, the quality and functional characteristics of processed potato products are closely linked to endogenous sugar metabolism in tubers, with the trehalose–sucrose metabolism playing a key role in processing adaptability. This study analyzed 333 accessions from a tetraploid potato natural population. The trehalose and sucrose content of potato tubers at harvest was quantified using the high-performance liquid chromatography (HPLC) method. Combined with whole-genome resequencing, a genome-wide association study (GWAS) was conducted to map regulatory loci and identify candidate genes. The results showed that relative trehalose content in tubers was 20.38–24.78, while relative sucrose content was 10.32–19.50. Frequency histograms for both sugars exhibited normal distributions characteristic of quantitative traits, and a positive correlation was observed between them. GWAS for trehalose identified 111 significant SNP loci, mainly on chromosomes 10 and 12, leading to the identification of 88 candidate genes. Kyoto encyclopedia of genes and genomes analysis (KEGG) revealed that trehalose-related genes were primarily involved in pathways such as ABC transporters, tricarboxylic acid (TCA) cycle, and cysteine and methionine metabolism. Candidate genes potentially regulating tuber trehalose content included GH10, GH28, GH127, UXS, UGT, PMEI, and MYB108. For sucrose, GWAS identified 279 significant SNP loci, mainly on chromosomes 5, 6, and 12, resulting in 111 candidate genes. KEGG enrichment analysis showed that sucrose-related genes were enriched in pathways including starch and sucrose metabolism, cyanoamino acid metabolism, and phenylpropanoid biosynthesis. Candidate genes potentially regulating tuber sucrose content included GH17, GH31,GH47, GH9A4, SPP1, BGLU12, GSA1, TPS8, cwINV4, HXK, UST, MYB5, MYB14, and WRKY11. Therefore, this study provides marker loci for trehalose and sucrose metabolism research, aiming to clarify their regulatory mechanisms and support potato variety improvement and superior germplasm development.

Low-temperature stress significantly limits plant growth, development, and productivity, posing a major environmental constraint. The potato (Solanum tuberosum L.) is particularly vulnerable to low temperatures, underscoring the crucial need to enhance cold tolerance in potato breeding efforts for sustainable production. Basic leucine zipper (bZIP) transcription factors serve as central regulators of plant developmental processes and stress responses; however, their functional role in cold tolerance in tetraploid potato remains poorly understood. Here, we report a systematic characterization of the bZIP gene family in tetraploid potato and provide preliminary evidence that StbZIP104 enhances plant cold tolerance. A total of 191 StbZIP genes were identified and classified into 11 subfamilies, exhibiting uneven chromosomal distribution and expansion primarily driven by whole-genome and segmental duplication. Promoter cis-element analysis, together with GO and KEGG enrichment analyses, indicated that StbZIP genes are broadly associated with hormone signaling, stress responses, signal transduction, and environmental adaptation. Expression profiling under low-temperature treatment revealed eight cold-inducible StbZIP genes (log₂FC ≥ 1 and FDR < 0.05), among which StbZIP104 was strongly induced (log₂FC ≥ 2) and showed 5.36-fold higher expression in highly cold-resistant cultivars than in cold-sensitive cultivars. Subcellular localization confirmed that StbZIP104 is a nuclear-localized protein. Functional validation confirmed that overexpressing StbZIP104 notably improved cold tolerance in transgenic Samsun NN tobacco (Nicotiana tabacum cv. Samsun NN). This was supported by heightened superoxide dismutase and peroxidase activities, increased levels of soluble protein and soluble sugars, and decreased malondialdehyde content compared to the wild type under cold stress. This study establishes a basis for the functional characterization of the bZIP gene family in tetraploid potato and serves as a theoretical reference for understanding the mechanisms that govern cold tolerance in this species.