目的探讨西洋参不同组织器官中总皂苷和单体皂苷量的差异及其与人参皂苷合成途径中鲨烯合成酶(SQS)和鲨烯环氧酶(SQE)基因表达量之间的关系。方法以4年生西洋参的14个组织器官为材料,索氏回流法提取总皂苷,采用HPLC法测定6种单体皂苷(人参皂苷Rg1、Re、Rb1、Rc、Rb2和Rd)的量,用香草醛-硫酸比色法测定总皂苷量。通过实时荧光定量PCR分析SQS和SQE基因在西洋参14个组织器官中的表达量。结果总皂苷和单体皂苷量在西洋参不同组织器官中差异非常显著(P<0.01)。除人参皂苷Rb2外,各单体皂苷及总皂苷之间均呈非常显著的正相关关系(P<0.01)。SQS和SQE基因在14个组织器官中的表达量具有非常显著的差异(P<0.01)并与人参皂苷Re、Rg1、Rb1、Rd和总皂苷量之间有显著的正相关关系(P<0.05)。结论西洋参不同组织器官中皂苷的量存在差异,SQS和SQE基因在人参皂苷合成途径中起着极其重要的作用。

Objective To examine the biological accumulation of total ginsenosides and their monomers,and determine their relationships with the expression of squalene synthase(SQS) and squalene epoxidase(SQE) genes that are involved in the ginsenoside biosynthetic pathway in different organs of Panax quinquefolius.Methods Fourteen organs of four year-old P.quinquefolius were used as materials.Total ginsenosides were extracted using the Soxhlet ginsenoside extraction method,and the contents of total ginsenosides and their monomers Rg1,Re,Rb1,Rc Rb2 and Rd in the organs were determined by the Vanillin-sulfuric Colorimetry and HLPC methods,respectively.The expressions of the SQS and SQE genes in the organs were profiled by real-time quantitative PCR.Results The biological accumulation of total ginsenosides and each of their monomers varied significantly(P0.01) in different parts of P.quinquefolius.Except for ginsenoside monomer Rb2,there were significantly positive correlations between total ginsenoside and monomers Re,Rg1,Rb1 and Rd(P0.01).The expressions of both SQS and SQE genes were extremely significantly different among the 14 plant parts(P0.01) and significantly positively correlated with the biological accumulation of total ginsenoside and monomers,Re,Rg1,Rb1 and Rd(P0.05).ConclusionThe results indicate that the SQS and SQE genes play the important roles in the biosynthesis of total gingenosides and their monomers.

吉林省科技厅资助项目(20100712,20080715);长春市科技局资助项目(长科合2007135号,长科合2008138号)