Fine Mapping and Candidate Genes Analysis for Regulatory Gene of Anthocyanin Synthesis in the Corolla, Shedding Light on Wild Potato Evolution

Petota includes more than 100 species (wild and cultivated), presenting a rich variety of corolla colors and associated traits. This variability provides important opportunities for investigating the differentiation of orthologous genes' functions and their evolutionary pathways. However, the genetic underpinnings of this diversity in corolla colors are still to be further explored. In our previous study, a locus responsible for corolla color in potato was mapped to a 740 kb region on chromosome 10, which contains the AN2 gene previously identified as a regulation gene for corolla color. In the present study, this locus was further refined to a 380 kb interval through recombinant analysis. Targeted analysis of anthocyanidins and carotenoids revealed that purple corollas exhibit significantly higher levels of petunidin and delphinidin, while showing significantly lower levels of lutein and beta-carotene compared to yellow corollas. Transcriptome and qRT-PCR analysis indicated that StMYB180, rather than AN2, is the candidate gene responsible for regulating coloration, specifically on the abaxial side of the corolla in potato. Expression analysis revealed that StMYB180 is exclusively highly expressed in corolla and leaf tissues, with purple coloration on the abaxial side of both corollas and leaves. Phylogenetic analysis further suggests that corolla color-regulatory genes may be closely tied to the origin and evolutionary trajectory of potato species. This study provides valuable insights into the regulation of tissue-specific expression of anthocyanin biosynthesis in potato and lays the groundwork for understanding the evolution of orthologous genes in the Petota section.