干旱胁迫对柴胡中皂苷合成关键酶基因表达及皂苷含量的影响  

Expression of key enzyme genes and content of saikosaponin in saikosaponin biosynthesis under drought stress in Bupleurum chinense

作　　者：张宇[1] 周自云[1] 夏鹏国[2] 梁宗锁[1,2] 刘书礼 刘之良 

机构地区：[1]西北农林科技大学生命科学学院,陕西杨凌712100 [2]浙江理工大学生命科学学院,浙江杭州310018 [3]四川逢春制药有限公司,四川中江610081

出　　处：《中国中药杂志》2016年第4期643-647,共5页China Journal of Chinese Materia Medica

基　　金：陕西省重大产业集群项目(2012KTCL02-07)

摘　　要：为了探究干旱胁迫对柴胡皂苷合成关键酶基因表达和皂苷含量的影响,以期从终产物,基因水平揭示柴胡皂苷合成对环境变化的响应。该研究以定植5个月的柴胡苗为研究材料,通过添加聚乙二醇(PEG)模拟干旱环境,利用HPLC测定不同胁迫程度下,柴胡根中皂苷a和d含量的变化,同时以β-tubulin为内参基因,采用荧光实时定量PCR(RT-q PCR)分析皂苷合成途径中4个关键酶3-羟基-3-甲基戊二酸单酰辅酶A还原酶(HMGR),异戊烯基焦磷酸异构酶(IPPI),法尼基焦磷酸合酶(FPS)和β-香树素合成酶(β-AS)基因的表达。通过研究发现,干旱胁迫处理显著提高了柴胡中皂苷的含量,且当PEG为10%时,柴胡皂苷a和d质量分数最高,分别达到0.648%,0.781%;同时,各基因表达量结果显示,4个关键酶基因的表达均呈现不同程度的上调,其中FPS和β-AS上调极显著(P<0.01);此外,相关性分析表明,HMGR,IPPI,FPS,β-AS的表达量和皂苷含量间存在显著正相关关系。因此,干旱胁迫下,柴胡通过调节皂苷合成关键酶基因的表达,来调节次生代谢物皂苷的合成,从而对逆境做出响应。To research the expression of key enzymes in saikosaponin biosynthesis and the content of saikosaponin under the drought stress,the study focused on the gene-level and the end product responses to environmental change. Taking the five months of Bupleurum chinense as research materials,the contents of saikosaponin A and saikosaponin D under different stress levels were measured by HPLC. The drought was simulated by poly ethylene glycol. The real-time fluorescence quantitative PCR was used to analyze the expression of four key enzymes genes HMGR,IPPI,FPS,β-AS and the expression of β-tubulin was set as a reference gene. The results showed that drought stress significantly improved the content of saikosaponin. The contents of SSa and SSd were highest researching0. 648% and 0. 781%,respectively when the concentration of PEG was 10%. Meanwhile,the results reflected that the expression of four key enzymes had risen differently and FPS,β-AS raised significantly（ P〈0. 01）. In addition,the results of correlation analysis showed that there was a significant positive correlation between the expression of the four key enzymes genes and the content of saikosaponin. In a word,the contents of secondary metabolites were regulated by the expression of key enzymes genes under the drought stress in B. chinense.

关 键 词：柴胡 干旱胁迫 皂苷 基因表达 

分 类 号：S567.79[农业科学—中草药栽培] Q943.2[农业科学—作物学]