Immunocytochemical localization of saikosaponin-d in vegetative organs of Bupleurum scorzonerifolium Willd.
Immunocytochemical localization of saikosaponin-d in vegetative organs of Bupleurum scorzonerifolium Willd.
复制标题
柴胡营养器官中柴胡皂苷-d的免疫细胞化学定位
DOI：
10.1186/1999-3110-54-32
复制
发表时间：
2013-12
影响因子：
3.4
通讯作者：
Cai X
中科院分区：
文献类型：
--
作者：
Zhao X;Zheng L;Si J;Miao Y;Peng Y;Cai X
背景
柴胡皂苷-d(SSD)是中草药柴胡的重要活性成分。到目前为止，柴胡皂苷在柴胡中的生物合成途径和生物合成部位尚不清楚。SSD的细胞定位有助于理解柴胡皂苷的生物合成和调控。
结果
在这项研究中，我们首次用组织化学和免疫电子显微镜研究了SSD在鳞毛藻组织和细胞中的定位。结果表明，柴胡皂苷在植物不同器官中的分布随成熟度的变化而变化。根、茎、叶中SSD金颗粒数量差异明显，主要集中在根中。金颗粒主要存在于液泡中，少量颗粒存在于原生质中，因此SSD主要储存在液泡中。
结论
我们推测，柴胡皂苷主要通过甲戊酸途径在幼嫩器官的原生质中合成，然后通过内质网(ER)或液泡融合运输到中央液泡，以保护植物免受自毒，积累更多的柴胡皂苷。
Background
Saikosaponin-d (SSd) is an important active component of Bupleurum scorzonerifolium Willd., a traditional Chinese medicinal herb. Thus far, the biosynthetic pathway and biosynthetic site of saikosaponins in Bupleurum are largely unknown. The cellular localization of SSd will help in understanding saikosaponin biosynthesis and regulation.
Results
In this study, we characterize for the first time the localization of SSd in B. scorzonerifolium tissues and cells using histochemistry and immunoelectron microscopy. The results show that the saikosaponin distribution in different plant organs changes as they mature. The number of SSd gold particles distinctly differed among the roots, stems, and leaves, with the particles mainly concentrated in the roots. The gold particles were mainly observed in vacuoles, with a few particles in the protoplasm; hence, SSd is mainly stored in vacuoles.
Conclusions
We speculate that saikosaponins are mainly synthesized via the mevalonate pathway in the protoplasm in young organs, and then transported to the central vacuole by the endoplasmic reticulum (ER) or the fusion of vacuoles, to protect plants from self-poisoning with the accumulation of more saikosaponins.