目的 克隆北柴胡Bupleurem chinense达玛烯二醇合成酶（dammarenediol synthase，DS）基因BcDS，并进行生物信息学及表达模式分析。方法 通过搜索转录组数据库，利用RT-PCR克隆开放阅读框（open reading frame，ORF）和启动子区。通过生物信息在线工具预测基因编码蛋白的理化性质、结构域、信号肽、三级结构等分子特征，利用Jalview软件进行氨基酸多序列比对，采用MEGA 11.0软件进行分子进化分析。运用实时荧光定量PCR检测基因表达模式。结果 BcDS ORF长2115 bp，编码的蛋白包涵704个氨基酸，相对分子质量为80 770，为酸不稳定的亲水蛋白，无跨膜结构域或信号肽。BcDS与人参、西洋参等植物DS的相似性高，具有达玛烯二醇合成酶特征结构域，且BcDS与人参、西洋参、三七等DS聚为一支。BcDS启动子区域含有响应环境及植物激素的顺式作用元件。BcDS在根中的表达量最高，分别为茎、叶和花中BcDS表达量的5.81、10.44和7.86倍，并受茉莉酸甲酯（methyl jasmonate，MeJA）和水杨酸（salicylic acid，SA）的显著诱导。结论 获得北柴胡BcDS基因序列特征，明确了BcDS根中高表达且受MeJA和SA诱导表达，为进一步研究基因在柴胡皂苷合成中的分子作用奠定基础。

Objective To clone dammarenediol synthase (DS) gene from Beicaihu (Bupleurum chinense) (BcDS) and carry out bioinformatics and expression pattern analysis. Methods By searching the transcriptome database, the open reading frame (ORF) and upstream promoter sequence of BcDS was cloned by PCR. The physicochemical properties, conserved domains, signal peptides, tertiary structure and other molecular characteristics of BcDS proteins were analyzed by bioinformatics online tools, and Jalview software was used for multiple sequences alignment of amino acid, and MEGA 11.0 software was used for evolutionary analysis. Quantitative PCR was employed for gene expression analyses. Results The ORF of BcDS was 2115 bp in length, encoding a 704 aa protein with a molecular weight of 80 770, which was an acid-labile protein with a certain hydrophilicity, no transmembrane domain and signal peptide, and BcDS had a characteristic domain of dammarediol synthase. BcDS was highly consistent with dammarediol synthase of Panax ginseng, Panax quiquefolium, and Panax notoginseng, and they were clustered in a branch in phylogenetic tree. BcDS’s promoter region conainedd cis-acting elements that respond to the environment and plant hormones. The results of qRT-PCR showed that the expression of BcDS was the highest in roots, which was 5.81, 10.44 and 7.86 folds of that in stems, leaves and flowers and was significantly induced by methyl jasmonateand salicylic acid. Conclusion The sequence and expression characteristics of BcDS gene were obtained, and the high expression of BcDS in roots was identified, which lay a foundation for further research on the gene in the synthesis pathway of saikosaponin of B. chinense.

R286.12

陕西省重点产业创新链项目（2022ZDLSF05-03）；陕西省重点研发计划项目（2022SF-542）；陕西省科技计划一般项目（青年项目）（2023-JC-QN-0944）；陕西省中医药管理局专项（2021-QYZL-02）；咸阳市创新科技领军人才项目（L2022CXNLRC009）；陕西中医药大学学科创新团队项目（2019-QN01）