[关键词]
[摘要]
目的 筛选适宜北柴胡Bupleurum chinense表达分析的内参基因,并分析不同部位中柴胡皂苷含量与其关键酶基因表达的关系。方法 以北柴胡根、茎、叶、果为实验材料,利用实时荧光定量PCR技术,选取Actin、α-tubublin、β-tubulin、Cyclophilin、EF-1α 5个常用的内参基因作为候选,以筛选到的最适内参基因为参考分析北柴胡基因ACAT、FPS、HMGR、IPPI、PMD、PMK、SE、SS、β-AS、UGT1、UGT3、UGT6、UGT8、UGT10、P450-7、P450-12的组织表达模式,用HPLC法检测柴胡皂苷a、柴胡皂苷c、柴胡皂苷d的含量,并用SPSS软件进行相关性分析。结果 以5个候选基因(EF-1α、Cyclophilin、Actin、β-tubulin、α-tubublin)中稳定性最好的EF-1α为内参基因,测定北柴胡16个关键酶基因表达量,表明ACAT、PMK、IPPI、SS、SE、UGT1、UGT3、UGT6、UGT8均在地上部分(茎、叶、果)表达量最高,HMGR、β-AS、P450-7、P450-12在根中表达量高于地上部分,PMD、FPS、UGT10则组织差异性不明显。以HPLC法检测柴胡皂苷含量在根中远高于地上部分(茎、叶、果)。相关性分析结果显示,16个关键酶基因间上游ACAT、HMGR、PMD、SE等多与下游P450-7、P450-12、UGT3、UGT6、UGT8等表现出了显著正相关(P<0.05),表明关键酶基因相互间密切相关,共同调控柴胡皂苷合成。16个关键酶基因与柴胡皂苷含量的相关性分析结果显示:HMGR、P450-7、P450-12与3种皂苷总和呈极显著正相关(P<0.01),β-AS与3种皂苷总和呈显著正相关(P<0.05),且HMGR、β-AS、P450-7、P450-12与单体皂苷a、c、d含量均呈显著正相关(P<0.05),这4个基因对于皂苷合成积累有重要影响。结论 柴胡皂苷合成途径中HMGR、β-AS、P450-7、P450-12基因表达与柴胡皂苷合成积累具有一致性,在调控皂苷合成方面有重要作用。
[Key word]
[Abstract]
Objective To select reference genes suitable for the expression analysis of Bupleurum chinense, and analyze the relationship between the content of saikosaponin and the gene expression of key enzymes in different tissues of B. chinense. Methods The roots, stems, leaves and fruits of B. chinense were used as test materials, and five commonly used internal reference genes of Actin, α-tubublin, β-tubulin, Cyclophilin and EF-1α were selected as candidates by real-time quantitative PCR. Based on the selected internal reference gences, tissue expression pattern of ACAT, FPS, HMGR, IPPI, PMD, PMK, SE, SS, β-AS, UGT1, UGT3, UGT6, UGT8, UGT10, P450-7 and P450-12 genes in B. chinense was analyzed. The content of saikosaponin a, saikosaponin c and saikosaponin d were determined by HPLC, and correlation analysis was performed by SPSS. Results The EF-1α gene with the best stability in the five candidate genes (EF-1α, Cyclophilin, Actin, β-tubulin, α-tubublin) was selected as the internal reference gene. The expression levels of 16 key enzymes in the roots of B. chinense were measured. The results showed that ACAT, PMK, IPPI, SS, SE, UGT1, UGT3, UGT6, and UGT8 were the highest in the aboveground parts, the levels of HMGR, β-AS, P450-7 and P450-12 were higher in the roots than those in the aboveground parts, but PMD, FPS and UGT10 were not significantly different in the tissues. The content of saponins in the root was much higher than that in the aerial parts (stem, leaf and fruit) by HPLC. The results of correlation analysis showed that 16 key enzyme genes in the upstream ACAT, HMGR, PMD, SE and so on were significantly correlated with downstream P450-7, P450-12, UGT3, UGT6 and UGT8 (P < 0.05). It showed that the key enzyme genes were closely related to each other and regulated the synthesis of saikosaponin in common. The correlation analysis between the 16 key enzyme genes and the content of saikosaponin showed:HMGR, P450-7, p450-12 and the total of three saponins were significantly positively correlated (P < 0.01), and β-AS was significantly correlated with the total content of three saponins (P < 0.05), and HMGR, P450-7, P450-12, and β-AS were significantly correlated with the monomer saponins a, c, d (P < 0.05). These four genes jointly regulated the synthesis of saikosaponin and had an important effect on the accumulation of saponin. Conclusion The HMGR, β-AS, P450-7 and P450-12 genes in the saikosaponin synthesis pathway have a consistent distribution in saikosaponin synthesis and play an important role in the regulation of saponin synthesis.
[中图分类号]
R282.12
[基金项目]
国家中药材产业技术体系项目(CARS-21)