ABSTRACT
Objective: Panax notoginseng is an important medicinal plant and its secondary metabolites, P. notoginseng saponins (PNS), synthesized by the mevalonate pathway are the active ingredients. The study on the gene of the key enzyme 3-hydroxy-3- methylglutaryl-coenzyme-A reductases (HMGR) in the mevalonate pathway is helpful for the regulation of PNS syntheses. Methods: The primers were designed according to P. ginseng HMGR (accession number: GU565097.1) from NCBI. Total RNA was extracted from the callus of P. notoginseng. The fragment of HMGR gene was amplified by reverse transcription PCR technology and analyzed. Results: Sequence analysis showed that the cDNA sequence of obtained fragment (PnHMGR) was 1 893 bp, containing an ORF spaning 1 725 bp, and exhibited 98%, 93%, and 80% sequence identity with HMGR in P. ginseng, Eleutherococcus senticosus, and Eucommia ulmoides. The cDNA was a new one as searching in the Genbank. The bioinformatic analysis showed that PnHMGR-encoding protein contained two transmembrane regions and the HMGR catalytic domain, without signal peptide. The expression level of PnHMGR was the highest when the callus of P. notoginseng has grown for 30 d. Conclusion: It is the first time to report HMGR gene isolated from P. notoginseng. The results will provide a groundwork for exploring the molecular function of PnHMGR involved in PNS biosynthesis based on the synthetic biology of P. notoginseng.