Abstract：
Panax ginseng is a perennial herb with the main active compounds of ginsenosides. Among the reported ginsenosides, ginsenoside Rg_1 not only has a wide range of medicinal functions and abundant content but also is one of the major ginsenoside for the quality evaluation of this herb in the Chinese Pharmacopoeia. The main biosynthesis pathway of ginsenoside Rg_1 in P. ginseng has been clarified, which lays a foundation for the comprehensive and in-depth analysis of the biosynthesis and regulatory mechanism of ginseno-side Rg_1. However, the biosynthesis of ginsenoside Rg_1 is associated with other complex processes involving a variety of regulatory genes and catalyzing enzyme genes, which remain to be studied comprehensively. With the transcriptome data of 344 root samples from 4-year-old P. ginseng plants and their corresponding ginsenoside Rg_1 content obtained in the previous study, this study screened out 217 differentially expressed genes(DEGs) with Rg_1 content changes by DEseq2 analysis in R language. Furthermore, the weighted gene co-expression network analysis(WGCNA) revealed 40 hub genes among the DEGs.Pearsoncorrelation analysis was further perforned to yield 20 candidate genes significantly correlated with ginsenoside Rg_1 content, and these genes were annotated to multiple metabolic processes including primary metabolism and secondary metabolism. Finally, the treatment of P. ginseng adventitious roots with methyl jasmonate indicated that 16 of these genes promoted the biosynthesis of ginsenoside Rg_1 in response to methyl jasmonate induction. Finally, one of the 16 genes was randomly selected to verify the function of the gene by genetic transformation and qRT-PCR and to confirm the rationality of the methodology of this study. The above results lay a foundation for studying the mechanism for regulation on the synthesis of ginsenoside Rg_1 and provide genetic resources for the industrial production of ginsenoside Rg_1.
摘要：
人参是多年生草本植物，主要活性成分为人参皂苷。在报道的人参皂苷中，人参皂苷Rg_1不仅具有广泛的药用功能和丰富的含量，而且是中国药典中用于质量评价的主要人参皂苷之一。阐明了人参皂苷Rg_1的主要生物合成途径,为全面深入地分析人参皂苷Rg_1的生物合成及其调控机制奠定了基础。然而,人参皂苷Rg_1的生物合成与涉及多种调控基因和催化酶基因的其他复杂过程有关,还有待全面研究。利用前期研究中获得的4年生人参植物的344份根样的转录组数据及其相应的人参皂苷Rg_1含量,本研究通过DEseq2分析在R语言中筛选出217个具有Rg_1含量变化的差异表达基因（DEGs）。此外，加权基因共表达网络分析（WGCNA）揭示了DEGs中的40个hub基因。进一步进行Pearson相关分析，得到20个候选基因与人参皂苷Rg_1含量显著相关，这些基因被注释为多个代谢过程，包括初级代谢和次级代谢。最后,茉莉酸甲酯对人参不定根的处理表明，这些基因中有16个响应茉莉酸甲酯的诱导而促进人参皂苷Rg_1的生物合成。最后,随机选取16个基因中的1个基因,通过遗传转化和qRT-PCR验证该基因的功能,证实本研究方法学的合理性。上述结果为研究人参皂苷Rg_1合成调控机制奠定了基础,为人参皂苷Rg_1的工业化生产提供了遗传资源。
