基于多组学的茶枝柑果皮多甲氧基黄酮积累机制研究

Exploring the Accumulation Mechanism of Polymethoxylated Flavones in Citrus reticulata ‘Chachi’ Peel Based on Multiomics

关键词:  茶枝柑  多甲氧基黄酮  茉莉酸  bZIP  转录因子  调控网络

Key words:  Citrus reticulata ‘Chachi’  polymethoxylated flavones  jasmonic acid  bZIP  transcription factor  regulatory network

摘要:

为探究茉莉酸（Jasmonic Acid,JA）对多甲氧基黄酮（Polymethoxylated Flavones,PMFs）积累的影响，本研究结合茶枝柑（Citrus reticulata ‘Chachi’）果皮转录组与代谢组数据，采用加权基因共表达网络分析（Weighted Gene Co-expression Network Analysis，WGCNA）筛选与PMFs、JA含量变化密切相关的基因共表达模块和候选调控因子，进一步构建PMFs生物合成的候选调控网络，并通过外源茉莉酸甲酯（Methyl Jasmonate，MeJA）处理进行验证。结果表明，茶枝柑果皮中PMFs含量随果实发育总体呈下降趋势，JA含量与PMFs含量呈显著正相关。茶枝柑果皮筛选出与PMFs、JA含量均高度相关的Blue模块，并从中鉴定出4个与苯丙烷-类黄酮代谢途径相关的关键结构基因、8个茉莉酸类ZIM结构域（Jasmonate ZIM-domain，JAZ）家族基因和15个碱性亮氨酸拉链（basic leucine zipper，bZIP）转录因子，成功构建“JAZ-bZIP-结构基因”候选调控网络。外源MeJA处理后，茶枝柑果皮中部分PMFs含量及类黄酮代谢相关候选基因表达水平发生显著变化，进一步说明JA参与茶枝柑果皮PMFs积累调控。本研究初步揭示了JA与PMFs积累之间的关联及其潜在调控机制，可为茶枝柑果实品质改良及广陈皮药效品质提升提供理论依据。

Abstract:

To investigate the effects of Jasmonic Acid (JA) on the accumulation of Polymethoxylated Flavones (PMFs),this study integrated transcriptomic and metabolomic data from the peel of Citrus reticulata ‘Chachi’.Weighted Gene Co-expression Network Analysis (WGCNA) was performed to identify gene co-expression modules and candidate regulatory factors closely associated with the dynamic changes in the content of PMFs and JA.A candidate regulatory network for the biosynthesis of PMFs was further constructed and validated via exogenous Methyl Jasmonate (MeJA) treatment.The results showed that PMFs content in C.reticulata ‘Chachi’ peel generally decreased during fruit development,and JA content exhibited a significant positive correlation with PMFs content.The Blue module,which was highly correlated with both PMFs and JA content in the peel,was screened out.Four key structural genes involved in the phenylpropaneflavonoid metabolic pathway,eight Jasmonate ZIM-domain (JAZ) family genes,and fifteen basic leucine zipper (bZIP) transcription factors were identified from this module,and a candidate “JAZ-bZIP-structural gene” regulatory network was established.Following exogenous MeJA application,significant alterations were observed in the content of partial PMFs and the expression of candidate flavonoid metabolism-related genes in the peel,further indicating that JA participated in the regulation of PMFs accumulation in C.reticulata ‘Chachi’.This study preliminarily reveals the association and underlying regulatory mechanism between JA and PMFs accumulation,providing a theoretical basis for fruit quality improvement of C.reticulata ‘Chachi’ and the medicinal quality enhancement of Citri Reticulatae Pericarpium.