Purple-leaf tea plants are of considerable interest because they show elevated anthocyanin contents. However, the underlying biosynthetic mechanisms of this are incompletely understood. We use metabolomic profiling to analyze anthocyanin accumulation patterns across different purple-leaf plant (‘Nanhan Ziya’) tissues and report that the second and third leaves have significantly higher anthocyanin levels than other tissue types. By integrating transcriptomic sequencing data, we systematically characterize the expression profiles of key genes involved in the anthocyanin biosynthesis pathway. Correlation analysis reveals that the expression levels of anthocyanin synthase (ANS) highly, significantly, and positively correlate with anthocyanin content, with a stronger association than other genes in the pathway. This suggests that ANS may function as a critical rate-limiting enzyme in anthocyanin synthesis in purple-leaf tea plants. Weighted gene co-expression network analysis revealed several transcription factors (e.g., MYB14, NAC35, bHLH90) strongly associated with anthocyanin accumulation. We elucidate the central regulatory role of ANS at the transcriptional level, construct a preliminary interaction network with key transcription factors for it, and provide theoretical foundations for further deciphering the anthocyanin biosynthesis mechanism and for breeding tea varieties with enhanced anthocyanin traits.
Li et al. (Mon,) studied this question.