乙烯对绞股蓝皂苷生物合成关键酶基因表达和皂苷含量的影响

Effects of ethylene on gypenoside biosynthesis-related key enzyme gene expression and gypenoside content in Gynostemma pentaphyllum

关键词:  绞股蓝, 乙烯, 皂苷, 基因表达, 植物器官

Key words:  Gynostemma pentaphyllum, ethylene, gypenoside, gene expression, plant organ

摘要:

以药食两用植物绞股蓝为材料,研究了植物激素乙烯对绞股蓝皂苷生物合成关键酶基因表达及皂苷含量的影响。该文采用荧光定量PCR技术,检测了乙烯利处理后绞股蓝不同器官中皂苷生物合成关键酶基因GpFPS、GpSS和GpSE的表达水平; 采用分光光度法及HPLC技术,测定了乙烯利处理对绞股蓝总皂苷和皂苷单体Rb₁、Rb₃和Rd含量的影响。结果表明:(1)外施乙烯利能够不同程度地上调GpFPS、GpSS和GpSE基因的表达水平,且3个基因的表达模式在不同器官间不同,而在同一器官中相似。(2)在乙烯利处理后3 d,所测各器官中的总皂苷含量与对照相比均有所上升,其中根、成熟叶和幼叶达到显著水平,但3个皂苷单体在不同器官中的增加或降低并不一致,以Rb₃含量最高。该结果为探索利用植物激素调控绞股蓝皂苷次生代谢提供了参考。

Abstract:

The effects of plant hormone ethylene on gypenoside biosynthesis-related key enzyme gene expression and gypenoside content in medicine-food plant Gynostemma pentaphyllum were analyzed in this study. Fluorescence quantitative PCR was employed to test the expression levels of GpFPS, GpSS and GpSE, key enzyme genes in saponin biosynthesis pathway in different organs of G. pentaphyllum treated with ethephon, while spectrophotometry and HPLC were used to assay the contents of total gypenoside and saponin monomer Rb₁, Rb₃ and Rd in G. pentaphyllum. The results were as follows:(1)The expression levels of GpFPS, GpSS and GpSE genes were up-regulated by addition of ethephon in different extents, and the expression patterns of these three genes were dissimilar in different organs, but similar in the same organ.(2)The contents of total gypenoside in all organs increased when compared with the control, and those in root, mature leaf and young leaf arrived at significant level 3 d after ethephon treatment; However, the three saponin monomers increased or decreased in organs were inconsistency, with Rb₃ had the highest content. The results provide reference for the research of using plant hormone to regulate the secondary metabolism in G. pentaphyllum.