Comprehensive Characterization of the C3HC4 RING Finger Gene Family in Potato ( L.): Insights into Their Involvement in Anthocyanin Biosynthesis.

The C3HC4 RING finger gene (RING-HC) family is a zinc finger protein crucial to plant growth. However, there have been no studies on the RING-HC gene family in potato. In this study, 77 putative s were identified in the potato genome and grouped into three clusters based on phylogenetic relationships, the chromosome distribution, gene structure, conserved motif, gene duplication events, and synteny relationships, and -acting elements were systematically analyzed. By analyzing RNA-seq data of potato cultivars, the candidate genes that might participate in tissue development, abiotic stress, especially drought stress, and anthocyanin biosynthesis were further determined. Finally, a gene ( annotated as ), which was highly expressed in pigmented potato tubers was focused on. StRNF4-like localized in the nucleus, and Y2H assays showed that it could interact with the anthocyanin-regulating transcription factors (TFs) StbHLH1 of potato tubers, which is localized in the nucleus and membrane. Transient assays showed that StRNF4-like repressed anthocyanin accumulation in the leaves of and by directly suppressing the activity of the dihydroflavonol reductase (DFR) promoter activated by StAN1 and StbHLH1. The results suggest that StRNF4-like might repress anthocyanin accumulation in potato tubers by interacting with StbHLH1. Our comprehensive analysis of the potato StRING-HCs family contributes valuable knowledge to the understanding of their functions in potato development, abiotic stress, hormone signaling, and anthocyanin biosynthesis.