Cloning and expression analysis of 3-hydroxy-3-methylglutaryl coenzyme A reductase (CcHMGR) genes in Cinnamomum camphora (L.) Presl

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is the first rate-limiting enzyme of terpenoid biosynthesis in the mevalonic acid pathway (MVA) pathway. It is an important regulatory site in terpenoids metabolism pathway in the cytoplasm. According to the transcriptome database of Cinnamomum camphora, two HMGRs named CcHMGR1 (GenBank:MN163055) and CcHMGR2 (GenBank:MN163056) were cloned by cDNA from C. camphora. The ORF of CcHMGR1 and CcHMGR2 is composed of 1 689 bp and 1 683 bp, respectively, encoding 562 and 560 amino acids. The bioinformatics analysis of CcHMGR1 and CcHMGR2 indicated that the molecular weight of the encoded protein is 59.819 kDa and 59.397 kDa, with a theoretically isoelectric point of 8.20 and 8.61, respectively. There are 2 transmembrane structures without signal peptide existing in the encoded amino acid of CcHMGRs. The analysis of sequence alignment and phylogenetic tree showed that the CcHMGRs belonged to the HMGR family. The camphor is divided into five chemitypes, according to the main chemical compounds in C. camphora. The results of the real time PCR indicated that the expression level of CcHMGRs in Cineol type was higher than that in Linalool type, iso-nerolidol type, Camphor type and Borneol type. CcHMGRs expressed highest in roots and lowest in branches. In this study, the cDNA full length of CcHMGRs were cloned from C. camphora for the first time. Our results revealed that the expression level of CcHMGRs were different among five chemical types and different plant tissues, and the research provides foundation for further study of the terpenoids biosynthetic pathway in C. camphora.