基于多组学技术的枯芩“中枯而飘”性状特征研究

Dead heart of pith-decayed Scutellariae Radix:a study based on multi-omics

“中枯而飘”是枯芩药材重要的性状鉴定特征,该文旨在利用多组学技术阐明枯芩“中枯而飘”性状特征的科学内涵。该研究运用代谢组学、转录组学技术并结合主成分分析(PCA)及偏最小二乘法判别分析(PLS-DA)等多元统计方法,系统比较了枯芩韧皮部、外层木质部、近枯心木质部在化学成分和基因表达方面的差异。研究结果表明,三者的黄酮苷及苷元含量存在显著差异,相较于韧皮部和外层木质部,近枯心木质部中黄芩苷、去甲汉黄芩素-7-O-β-D-葡萄糖醛酸苷、千层纸素A-7-O-β-D-葡萄糖醛酸苷、汉黄芩苷等黄酮苷类成分含量显著较低,而3,5,7,2′,6′-五羟基二氢黄酮、黄芩素、汉黄芩素、千层纸素A等黄酮苷元类成分含量显著较高。三者的差异表达基因主要集中在苯丙烷代谢、类黄酮生物合成、ABC转运蛋白、植物MAPK信号转导通路等KEGG途径。该文系统地阐明了高年限黄芩“中枯而飘”性状特征的物质基础,即近枯心木质部的黄酮苷元含量明显升高,黄酮苷水解、木间木栓合成、程序性凋亡等代谢通路基因表达显著上调,为引导枯芩药材的高品质生产提供了理论依据。

Dead heart is an important trait of pith-decayed Scutellariae Radix.The purpose of this study was to clarify the scientific connotation of the dead heart using multi-omics.Metabolomics and transcriptomics combined with multivariate statistical analysis such as principal component analysis(PCA)and partial least squares discriminant analysis(PLS-DA)were used to systematically compare the differences in chemical composition and gene expression among phloem,outer xylem and near-dead xylem of pith-decayed Scutella-riae Radix.The results revealed significant differences in the contents of flavonoid glycosides and aglycones among the three parts.Compared with phloem and outer xylem,near-dead xylem had markedly lowered content of flavonoid glycosides(including baicalin,norwogonin-7-O-β-D-glucuronide,oroxylin A-7-O-β-D-glucuronide,and wogonoside)while markedly increased content of aglycones(including 3,5,7,2′,6′-pentahydroxy dihydroflavone,baicalin,wogonin,and oroxylin A).The differentially expressed genes were mainly concentrated in KEGG pathways such as phenylpropanoid metabolism,flavonoid biosynthesis,ABC transporter,and plant MAPK signal transduction pathway.This study systematically elucidated the material basis of the dead heart of pith-decayed Scutellariae Radix with multiple growing years.Specifically,the content of flavonoid aglycones was significantly increased in the near-dead xylem,and the gene expression of metabolic pathways such as flavonoid glycoside hydrolysis,interxylary cork development and programmed apoptosis was significantly up-regulated.This study provided a theoretical basis for guiding the high-quality production of pith-decayed Scutellariae Radix.