基于转录组学解析白光诱导采后桃形李果实花色苷合成的机制

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

摘要:

目的 探究白光诱导对采后桃形李果实花色苷合成的调控机制。方法 以黑暗处理为对照，测定白光处理对桃形李果实花色苷质量分数的影响。通过加权基因共表达网络分析（WGCNA）筛选与花色苷合成相关的共表达模块及核心基因，并结合实时荧光定量PCR（RT-qPCR）验证基因表达水平。利用酵母单杂交（Y1H）方法验证转录因子与PsANS启动子的互作关系。结果 白光处理可显著提高桃形李果实花色苷质量分数。WGCNA结果显示，MEdarkred和MElightcyan1模块与花色苷合成显著相关，共筛选获得12个花色苷合成相关基因，其中PsANS为核心基因。RT-qPCR结果证实，PsANS基因与筛选得到的转录因子表达均明显上调。Y1H试验结果表明，转录因子PsbHLH2、PsbZIP4、PsGRAS1、PsMYB1可与PsANS启动子结合。结论 白光可通过激活以PsANS为核心基因的转录调控网络，促进采后桃形李果实花色苷的积累。

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.