Genome-Wide Characterization and Transcriptomic Analysis Reveal Light-Quality-Responsive RING Zinc Finger Genes in Potatoes

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.