目的 克隆刺五加香叶基焦磷酸合成酶（geranyl pyrophosphate synthase，GPS）基因的cDNA序列并分析基因序列特征、不同器官中基因表达水平及其与皂苷含量的相关性。方法 提取刺五加的RNA，逆转录为cDNA。根据转录组测序结果中编码GPS的unigene（c37362.graph_c0），设计特异性引物，经过PCR扩增GPS基因的cDNA全长。利用实时荧光定量PCR（qRT-PCR）分析GPS基因在不同器官中的表达水平，并通过分光光度法检测刺五加总皂苷含量。结果 克隆得到长1 260 bp、编码419个氨基酸的刺五加GPS基因cDNA。GPS蛋白定位于线粒体内且不存在跨膜区域。GPS基因在各个器官中均有表达，在叶片中的表达量最高，是根中表达量的5.26倍。GPS基因的相对表达量与皂苷量呈现出同升同降的变化趋势，表现为显著正相关关系（r=0.851，P<0.05）。结论 首次克隆获得刺五加GPS基因的cDNA全长序列，明确了刺五加GPS基因的表达量与皂苷含量之间存在正相关关系。

Objective To clone cDNA sequence of geranyl pyrophosphate synthase (GPS) gene from Eleutherococcus senticosus and analyze genetic characteristics, gene expression level in different organs and the correlation between GPS gene expression and saponins content. Methods RNA was extracted from E. senticosus and reverse transcribed into cDNA. Gene specific primers were designed according to the unigene (c37362.graph_c0) of GPS from transcriptome sequencing data. The full length of the GPS gene cDNA was amplified by PCR. The expression level of GPS gene in different organs was analyzed by qRT-PCR. The content of E. senticosus saponins was detected by spectrophotometry method. Results GPS gene cDNA was cloned from E. senticosus and encodes 419 amino acids with full length of 1 260 bp. GPS protein located in mitochondria does not have transmembrane region. The GPS gene was expressed in each organ and had the highest expression in blade, which is 5.26 times in root. The relative expression of GPS gene and content of saponin showed the same trend and significant positive correlation (r=0.851, P < 0.05). Conclusion The whole length of cDNA sequence of GPS gene is cloned for the first time, and there is a positive correlation between the expression level of GPS gene and the saponin content of E. senticosus.

国家自然科学基金项目（31570683）；华北理工大学培育基金资助（SP201508）