走马胎三萜皂苷合成相关基因表达分析北大核心CSCD

走马胎是我国华南地区重要的民族药物,其体内的次生代谢物三萜皂苷具有多种药用功效。为了解三萜皂苷含量变化以及生物合成通路相关基因的调控规律,该研究对走马胎在不同组织部位以及不同外源激素处理下所呈现的表达模式进行了比较分析。结果表明:(1)三萜皂苷含量在不同组织部位间和外源激素处理下均存在显著差异,具体表现为根部组织的含量显著高于叶部组织的,而用外源水杨酸(SA)与茉莉酸甲酯(MeJA)喷施处理后其含量低于对照组(CK)。(2)对这两个差异比较组进行qRT-PCR分析结果显示,相比叶部组织,在根部组织中AkPMD、AkHDS、AkSS、AkSM以及与三萜皂苷合成相关的走马胎P450家族、UGT家族基因皆有不同程度的上调;外源SA与MeJA处理会导致合成途径上游的AkPMD、AkHDS、AkSS、AkSM上调,而下游的P450家族、UGT家族基因则有所下调。因此,通过对不同组织部位和不同外源激素处理这两种差异表达模式的比较研究,可推测在这两种表达模式下走马胎三萜皂苷的合成更多地与下游特异化修饰的酶相关。

Expression analysis of triterpenoid saponin biosynthesis related genes in Ardisia gigantifolia

Ardisia gigantifolia is an important ethnic medicine in South China, and its secondary metabolites, triterpenoid saponins, have various medicinal effects. In order to understand the changes of triterpenoid saponin contents and the regulation of genes related to biosynthesis pathway, a comparative study was carried out between the different tissue groups and different exogenous hormone groups with different contents of triterpene saponins. The results were as follows:(1)There were significant differences in the content of triterpene saponins in both different tissue sites and exogenous hormone treatments, the content of root tissue was significantly higher than that of leaf tissue, and the contents of salicylic acid(SA)and methyl jasmonate(MeJA)after exogenous spray treatment were lower than that of the control group(CK).(2)qRT-PCR results of these two difference comparison groups showed that AkPMD, AkHDS, AkSS, AkSM, P450 family and UGT family genes related to triterpenoid saponins synthesis were all up-regulated in root tissues compared with leaf tissues. In addition, SA and MeJA treatments resulted in up-regulation of genes in upstream, including AkPMD, AkHDS, AkSS and AkSM, while down-regulation of genes involved in the P450 family and UGT family in downstream. Therefore, by comparing the two different expression patterns in different tissue sites and different exogenous hormone treatments, it is suggested that the synthesis of A. gigantifolia triterpenoid saponins may be more related to the downstream specially modified enzymes in both of these two expression modes.