As key regulators of the Jasmonates (JAs) signal transduction pathway, JAZ protein, and MYC transcription factors are imperative for plant response to external environmental changes, growth, and development. In this study, 18 StJAZs and 12 StMYCs were identified in potatoes. Their chromosomal position, phylogenetic development, gene structure, and promoter cis-acting parts of the StJAZ genes were analyzed. In addition, Protein–Protein Interaction (PPI) network analysis of StJAZ and StMYC gene families and yeast two-hybrid assay demonstrated that five StMYCs can interact with 16 StJAZs, which provides new insights into the operation mechanism of StJAZs and StMYCs in JA signal response. Moreover, we explored the expression profiles of StJAZs and StMYCs genes in different tissues and during abiotic stresses by RNA-seq data. Based on the PPI network and transcriptome data, the genes StJAZ11, StJAZ16, and StMYC6 were chosen for further qRT-PCR study under salt or mannitol treatment. Under mannitol-induced drought or salinity treatment, the expression patterns of StMYC6, StJAZ11, and StJAZ16 were different, indicating that the JAZ protein and MYC transcription factor may be engaged in the response of potatoes to abiotic stress, which opened up a new research direction for the genetic improvement of potatoes in response to environmental stress.

Potato (Solanum tuberosum L.), cultivated worldwide for its nutrient-rich underground tubers, represents a crucial staple crop whose yield is primarily determined by both tuber number and tuber size. TCP transcription factors, especially TCP containing miR319 binding sites, play pivotal roles in plant growth and development, yet their functions in potato tuber number and size remain largely unexplored. In this study, we systematically identified 32 TCP genes in potato harboring the conserved TCP domain, among which six were predicted to contain binding sites for Stu-miR319. Semi-quantitative experiments revealed that StTCP10 exhibited the highest expression levels in stolons, swollen stolons, and tuber tissues compared to other StTCP genes containing miR319 binding sites. To elucidate its biological function, we generated StTCP10-overexpressing transgenic potato lines through Agrobacterium-mediated genetic transformation. Phenotypic analysis demonstrated that overexpression of StTCP10 reduced tuber number per plant while enhancing tuber size, with no significant change in total yield. These findings reveal that StTCP10 with Stu-miR319 binding sites plays a critical role in tuber size and mediates the trade-off between tuber size and number, providing novel insights into the molecular breeding aimed at improving tuber size.