Enzymatic browning markedly reduces the processing quality and economic value of potatoes. This study evaluated the effects of copper sulfate (CuSO₄) on potato growth, yield, and enzymatic browning. Quantitative analysis of browning-related enzymes, organic acids, free amino acids, and the browning index (BI) was conducted using high-performance liquid chromatography and non-contact colorimetric technology. Moderate Cu²⁺ (0.078–0.157 mmol·L⁻¹) supply enhanced photosynthetic capacity, biomass, and starch accumulation, whereas excessive Cu induced oxidative stress, increased PPO activity, phenolic accumulation, and BI. Metabolic profiling revealed that Cu²⁺ activates PPO via its copper-binding sites and reprograms amino acid and organic acid metabolism—upregulating arginine and proline while downregulating isoleucine, leucine, phenylalanine, lysine, citrate, and chlorogenic acid, all strongly correlated with BI. These findings highlight the dual role of copper in yield formation and enzymatic browning, introducing metabolic reprogramming as a potential mechanism for optimizing Cu fertilization to balance productivity and postharvest quality.

To investigate the role of potassium in the regulation of potato growth, dynamic changes in starch–sugar metabolism, and processing quality. In this study, “Gannong Potato No. 9” was used as the test material, and five potassium concentration treatments of 0, 9.4, 23.5, 28.5, and 37.6 mmol/L were set. The results showed that moderate application of potassium (23.5 mmol/L) significantly enhanced plant height, stem thickness, and tuber yield. It also promotes starch accumulation in all tissues and reduces sucrose, fructose, and glucose content, thus optimizing processing quality. Dynamic analyses showed that potassium affects carbohydrate transport and partitioning among tissues by regulating the direction of carbon partitioning and the rate of conversion. Correlation analysis confirmed the synergistic effect of starch–sugar metabolism among tissues, forming a spatio-temporally linked carbon allocation network. This study reveals the pivotal role of potash in potato starch–sugar metabolism and provides a theoretical basis for precision potassium application and quality improvement.

RING-zf E3 ligases play key roles in plant development and light signaling, but their genome-wide characterization and light-responsive functions in potatoes remain largely unexplored. In this study, we identified 291 StRING-zf genes containing complete RING domains in the potato genome and classified them into four major RING domain types, with RING-H2 being the predominant and structurally conserved group. Evolutionary analyses indicated that gene duplication contributed to the expansion of the StRING-zf genes, while promoter analysis revealed abundant cis-regulatory elements associated with light, hormones, and abiotic stress responses. Transcriptome analysis of the terminal leaflets of the third leaves of potato seedlings under different light qualities, combined with qRT-PCR validation, revealed diverse and gene-specific expression patterns among StRING-zf genes. Five candidate genes (Soltu.DM.01G022260.1, Soltu.DM.04G001050.1, Soltu.DM.10G023720.1, Soltu.DM.11G009040.1, and Soltu.DM.11G017440.1) exhibited distinct light-quality-dependent expression responses. These expression patterns provide preliminary evidence for their potential involvement in light-responsive regulatory processes and ubiquitin-mediated protein modification. Overall, this study provides a comprehensive genomic and transcriptomic resource for elucidating the evolutionary characteristics and potential functions of the StRING-zf genes and identifies candidate genes for further functional validation of light-responsive mechanisms in potatoes.