Molecular characterization of 3-hydroxy-3-methylglutaryl-CoA synthase gene from Dendrobium nobile / 中草药

ABSTRACT

Objective: To clone and characterize a 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS) gene DnHMGS in Dendrobium nobile. Methods: RT-PCR and RACE technologies were used for gene cloning. Characteristics including the physicochemical properties and conserved domain of the deduced DnHMGS protein were determined by a series of bioinformatics tools. The analyses of multiple alignment and phylogenetic tree were performed by DNASTAR and MEGA softwares, respectively. qRT-PCR was employed to examine the tissue specific expression pattern of DnHMGS. Results: The full length cDNA of DnHMGS was 1 816 bp (GenBank accession No. KX789180) and encoded a 474-amino-acid protein with a molecular weight of 52 458.47 and an isoelectric point (pI) of 5.98. The deduced DnHMGS protein, like other HMGS proteins, constituted typical domain and active site. Multiple sequence alignment and phylogenetic analyses demonstrated that DnHMGS was closely related to Ananas comosus, rice, and maize monocots. Proteins analysis revealed that DnHMGS was expressed in the three included organs. The transcripts were the most abundant in the leaves with more than twice that in the roots and stems. However, the expression of DnHMGS changed to stems > leaves > roots when D. nobile infected by Mycena sp. Conclusion: The full length cDNA of DnHMGS is indentified from D. nobile for the first time. Molecular characterization of DnHMGS will be useful for further functional elucidation of the gene involving in isoprenoid biosynthesis pathway in D. nobile, and help us understand the molecular mechanism of Mycena sp. which better encourages the biosynthesis of dendrobine.