Elucidating the Mechanism of White Light-induced Anthocyanin Synthesis in Postharvest Taoxingli Plum Fruits via Transcriptomics

Abstract:

Objective This study aimed to investigate the regulatory mechanism of white light-induced anthocyanin synthesis in postharvest Taoxingli plum fruits. Method With dark treatment as the control, the effect of white light treatment on the mass fraction of anthocyanins in Taoxingli plum fruits was measured. Weighted gene co-expression network analysis (WGCNA) was performed to screen co-expression modules and core genes related to anthocyanin synthesis. Reverse transcription real-time quantitative PCR (RT-qPCR) was employed to validate gene expression levels. Yeast one-hybrid (Y1H) assay was employed to verify the interactions between transcription factors and the PsANS promoter. Result White light treatment significantly increased the mass fraction of anthocyanins in Taoxingli plum fruits. WGCNA results revealed that the MEdarkred and MElightcyan1 modules were significantly correlated with anthocyanin synthesis, containing 12 anthocyanin synthesis-related genes, among which PsANS was identified as the core gene. RT-qPCR results confirmed the upregulated expression of PsANS gene and selected transcription factors. Y1H assay results demonstrated that transcription factors (PsbHLH2, PsbZIP4, PsGRAS1, and PsMYB1) could bind to the PsANS promoter. Conclusion White light promotes postharvest anthocyanin accumulation in Taoxingli plum fruits by activating the PsANS-centered transcriptional regulatory network.