Integrated metabolome and transcriptome analysis provides insights into anthocyanin biosynthesis in Portulaca oleracea

Pigment synthesis pathways in Caryophyllales have long been debated, with uncertainties surrounding the biosynthesis and regulation of anthocyanins in representative species. Portulaca oleracea provides a suitable model to clarify these mechanisms, which is valuable for understanding pigment metabolism and informing molecular breeding within Caryophyllales. Using a systematic multi-omics approach, we elucidated the anthocyanin biosynthesis mechanism in P. oleracea. Peonidin-3-O-glucoside was identified as the predominant anthocyanin component, and its abundance closely correlated with organ-specific coloration. We identified twenty-one key structural genes in the anthocyanin pathway (including CHS, DFR, ANS, and UFGT) and eleven transcription factors regulating anthocyanin accumulation, all showing distinct tissue-specific expression patterns. Notably, although the canonical anthocyanin transporter TT19 is absent in P. oleracea, a GST family gene (evm.TU.LG12.1168) was strongly associated with anthocyanin accumulation, suggesting a potential role in vacuolar transport. This work establishes a systematic molecular framework for anthocyanin biosynthesis and regulation in P. oleracea, highlights peonidin-3-O-glucoside as the primary pigment determinant of organ coloration, and proposes a GST-mediated transport mechanism in the absence of TT19. These findings offer theoretical insights for pigment metabolism research and provide a foundation for molecular breeding strategies across Caryophyllales.