Isolation and Characterization of GDP-D-mannose 3, 5-epimerase (GME) Gene Impressive in Vitamin C Biosynthesis Pathway

Document Type : Original Article


Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran


L-ascorbate acid is the scientific and common name for vitamin C. This vitamin is derived from L-threo-hex-2-enono-1,4-lactone. GME enzyme can modify GDP-Dmannose via epimerase effect and turns it to GDP-l-galactose. Thus, it creates interaction and relation between the synthetic pathway of vitamin C and the synthetic pathway of cell wall polysaccharides. Also, GEM enzyme produces GDP-l-glucose via another epimerase effect on GDP-l-galactose which is recognized as a new intermediate in vitamin C pathway of plants. In the biosynthesis pathway of vitamin C, GME has the most amount of protein protection. In this research, the GME gene of Actinidia deliciosa cultivar Hayward was cloned into the pTG19 plasmid. Sequencing analysis of the GME gene showed that this fragment contains 1161 bp. Results of blast showed that our sequence had high similarity (1973 score) with Actinidia deliciosa cultivar Qinmei and lowest similarity (1002 score) with Musa acuminate. According to the results of this study both phylogenic trees (DNA and protein) were divided into 7 separate groups. Also, Chlamydomonas reinhardtii and Oryza sativa Japonica in this dendrogram were placed in a separate group. Based on the results, Vitis vinifera was placed in two distinct groups in DNA and protein phylogeny trees. In contrast to DNA phylogenic tree in the protein phylogenic tree, all Solanums plants are grouped in one group that in dictate, although they are different in DNA sequencing, they are very similar in protein sequences.