Expression Analysis of GTP Cyclohydrolase I Gene under Abiotic Stresses in Grape (Vitis vinifera L.)

GTP cyclohydrolase I (gtpch I, EC 3.5.4.16) catalyzes the conversion of GTP to dihydroneopterin triphosphate and formic acid through a complex series of reactions. This reaction is the first committed step in the biosynthesis of FH4 (tetrahydrofolate) in plants and certain microorganisms, and BH4 (tetrahydrobiopterin) in mammals. Folates are comprised of a pABA (p-aminobenzoate) unit condensed with a pterin ring derived from GTP and a variable number of glutamate moieties. The expression analysis of a gtpch I gene was studied under abiotic and oxidative stress conditions in grape (Vitis vinifera L. cv. Askari) leaf by Semi-quantitative RT-PCR. The grape gtpch I gene was found to be differentially induced under abiotic stress conditions. The transcript level of Vvgtpch I was decrease under abiotic stress conditions such as drought, salt, and heat. Under diamide, AlCl3, ABA, and SA treatments, it was also decreased the transcripts amount of Vvgtpch I, whereas its expression was increased under H2O2, CuSO4, CdCl3, and CoCl2.