Isolation and cloning of 3-hydroxy-3-methylglutaryl-coenzyme reductase gene a from fennel (F.Vulgar)

In higher plants isoprenoid components are synthesized from two independent pathways including the Mevalonic acid (MVA) and the 2-C-methyl-D-erythritol 4-phosphate (MEP), which is needed for normal growth of plant and as well as the response reaction to environmental stress. The first step of the biosynthesis of plant isoprenoids is conversion of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-COA) to Mevalonic acid, which is carried out by the enzyme 3-hydroxy-3-methyl-glutaryl-CoA-reductase (HMGR). We employed homologous genes in this family for detection of their conserved sequence and primer designing. The HMGR gene was amplified using polymerase chain reaction in a fennel ecotype named Sari and was cloned via TA-cloning method. Nucleotide blast (BLASTn) analysis, was confirmed a high similarity for this sequence with other plant HMGRs, especially HMG-COA reductase from Centella asiatica plant (KF925529.1). This HMGR gene sequence in fennel had 1661 bp with an encoded region as length as 1589 base pairs, which contains two transition and catalytic domains. This ORF region encodes a protein with 553 amino acids with 59.816 kDa of molecular weight and an isoelectric point about 8.40. The molecular modeling of the sequence using the Model Swiss server showed that this sequence is a new type of HMGR, containing all of structural and functional domains and similar to other HMGRs in plant division. By having this new sequence for fennel, we can study the expression profiling of this gene in different organs, identification of polymorphism between their population and gene transformation studies using expression vectors.