目的:建立可用于甘草HMGR,SQS1,β-AS合酶基因CNVs测定的稳定可靠的检测体系。方法:利用Real timePCR方法对甘草HMGR,SQS1,β-AS合酶基因CNVs进行测定。结果:在HMGR,SQS1,β-AS合酶基因以及内标基因lectin的定量检测实验中,其定量反应的Ct值分别在25.82~25.88,29.01~29.08,15.52~15.56,19.06~19.08变化,SD分别是0.033,0.032,0.024,0.011,其CV分别是0.12%,0.22%,0.16%,0.06%。结论:所建立的Real time PCR体系重复性好,检测系统工作稳定可靠,可用于甘草HMGR,SQS1,β-AS基因的CNVs筛选。
目的:对甘草道地性形成机制进行探索。方法:在GenBank中检索β-香树酯醇合成酶(β-AS)基因,进行序列比对并找出序列保守区,用primer premier 5.0软件设计引物,对3个不同产地甘草材料的β-AS基因进行扩增、测序,用MegAlign软件进行序列分析并构建系统树。在表达差异实验中,对来自3个产地的9份甘草材料进行总RNA提取,逆转录得到cDNA,以甘草18S基因为内参,PCR扩增后进行相对表达量分析。结果:在序列多态性实验中,9个样品的β-AS序列经比对分析共发现108处变异位点,内含子变异位点数高于外显子变异位点数两倍。在表达差异实验中内蒙组、甘肃组和宁夏组的甘草β-AS基因平均相对表达量有显著性差异。结论:不同产地甘草β-AS基因多态性的差异以及表达量的差异,可能是导致甘草道地性形成的原因之一。
The rate-limiting enzyme in the mevalonic acid(MVA)pathway which can lead to triterpenoid saponin glycyrrhizic acid(GA)is 3-hydroxy-3-methylglutaryl-CoA reductase(HMGR).In order to reveal the effect of copy number variation in the HMGR gene on the MVA pathway,the HMGR gene from Glycyrrhiza uralensis Fisch.(GuHMGR)was cloned and over-expressed in Pichia pastoris GS115.Six recombinant P.pastoris strains containing different copy numbers of the GuHMGR gene were obtained and the content of ergosterol was analyzed by HPLC.The results showed that all the recombinant P.pastoris strains contained more ergosterol than the negative control and the strains with 8 and 44 copies contained significantly more ergosterol than the other strains.However,as the copy number increased,the content of ergosterol showed an increasing–decreasing–increasing pattern.This study provides a rationale for increasing the content of GA through over-expressing the GuHMGR gene in cultivars of G.uralensis.
Ying LiuXiaoqing ZhuWendong LiHao WenYa GaoYong LiuChunsheng Liu
甘草为常用中药材,具有补脾益气、清热解毒、祛痰止咳、缓急止痛和调和诸药等作用。甘草酸是甘草中的主要活性成分,其生物合成途径受到许多酶的调控,其中3-羟基-3-甲基戊二酰CoA还原酶(3-hydroxy-3-methylglutary CoA reductase,HMGR)催化3-羟基-3-甲基戊二酰辅酶A(3-hydroxy-3-methylglutary CoA,HMG-CoA)生成甲羟戊酸(MVA),是该途径中的第一个限速酶。本文克隆了甘草HMGR基因cDNA序列,对其进行序列分析,并与其他物种进行序列比对。构建了原核表达载体,诱导其外源表达及酶促反应,并利用TLC及GC-MS对产物进行检测。结果表明本文克隆得到的HMGR序列能很好的完成特定的酶促反应任务。由于HMGR基因在甘草酸生物合成途径中的重要作用,因此本实验的研究结果对于在分子水平上揭示高品质甘草的形成机制具有一定的意义。