Molecular Characterization of Tissue-Specific Anthocyanin Biosynthesis in Potato Stamens

While stamen-focused research has predominantly examined flowering ornamental species, the tissue-specific regulatory mechanisms governing anthocyanin biosynthesis in potato stamens remain poorly understood. To characterize the tissue-specific regulatory mechanisms controlling anthocyanin biosynthesis in potato reproductive and storage organs, this investigation employed the red stamen mutant line 'BF1811-8' and the commercial cultivar 'Atlantic' as experimental models. Anthocyanin composition and quantification were determined using high-performance liquid chromatography (HPLC), while RNA-sequencing coupled with quantitative real-time PCR validation enabled comprehensive analysis of differential gene expression patterns within the anthocyanin biosynthetic pathway. Biochemical analysis revealed complete absence of anthocyanins across all examined tissues in 'Atlantic', whereas 'BF1811-8' exhibited tissue-specific anthocyanin profiles: stamens accumulated delphinidin and pelargonidin, while tuber skin and flesh primarily contained pelargonidin and peonidin. Gene ontology and KEGG pathway enrichment analysis of differentially expressed genes identified significant representation within secondary metabolism, flavonoid biosynthesis, and pigmentation processes. The transcription factors <i>StMYB4</i> and <i>StMYBA1</i> demonstrated positive regulatory roles in anthocyanin biosynthesis within tuber flesh and skin, respectively, while exhibiting coordinated expression with structural genes including <i>CHS</i>, <i>DFR</i>, <i>ANS</i>, and <i>GST</i>. Notably, <i>StbHLH94</i> showed stamen-specific regulatory activity and demonstrated transcriptional co-regulation with <i>3GT</i>. These findings provide crucial insights into the tissue-specific regulatory architecture governing potato anthocyanin biosynthesis, establishing a foundation for elucidating molecular mechanisms underlying tissue-specific pigmentation and advancing functional cultivar development.