Abstract
The 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase (HDS) gene and the 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase (HDR) gene are two important genes in the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. In this study, we reported the isolation and characterization of full-length HDS (MF101802) and HDR (MF159558) from Pyropia haitanensis. Characteristics of 3-D structures of the PhHDS and PhHDR proteins were analysed respectively. The results showed that the full-length cDNA of PhHDS, which is 1801 bp long, contained a 1455 bp open reading frame (ORF) encoding a putative 484 amino acid residue protein with a predicted molecular mass of 51.60 kDa. Meanwhile, the full-length cDNA of PhHDR was 1668 bp and contained a 1434 bp ORF encoding a putative 477 amino acid 2 residue protein with a predicted molecular mass of 51.49 kDa. The expression levels of the two genes were higher in conchocelis than that in leafy thallus. Additionally, the expression levels could be influenced by light, temperature and salinity and induced by methyl jasmonate (MJ) and salicylic acid (SA). This study contributed to our in-depth understanding of the roles of PhHDS and PhHDR in terpenoid biosynthesis in Pyropia haitanensis and the regulation of the two genes by external environments.
Highlights
Terpenoids are a kind of biological secondary metabolite that are widespread in nature
A 435 bp PhHDR DNA fragment amplified with the HDRF/HDRR primer pair was proven to be a partial sequence from hydroxy-2-methyl-2(E)-butenyl-4-diphosphate reductase (HDR) from pyropia haitanensis
The methylD-erythritol 4-phosphate (MEP) pathway exists in plant plastids, and is one of the major metabolic pathways for the synthesis of secondary metabolites
Summary
Terpenoids are a kind of biological secondary metabolite that are widespread in nature. The MEP pathway exists in pathogens, algae and higher plants, including important human pathogens, such as Mycobacterium tuberculosis and malaria parasites[8,9]. The two pathways both use isopentenyl pyrophosphate (IPP) as a precursor for downstream terpene biosynthesis, and the differences between the two pathways are the formation mechanisms for IPP and its isomer diallylene pyrophosphate (DMAPP). The 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase (HDS) and 1-hydroxy-2-methyl-2(E)-butenyl-4-diphosphate reductase (HDR) genes participate in the last two steps of terpenoid metabolism in the MEP pathway. The results helped further our understanding of these two important genes in the MEP pathway and provided a practical way to study the molecular mechanism associated with terpenoid biosynthesis in Pyropia haitanensis. Analysis of the expression levels of these terpenoid biosynthesis genes in different environments will prove that Pyropia haitanensis has a unique physiological adaptation mechanism to different environments
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
