The Expression and Enzyme Activity of the Cytosolic Glutathione Reductase was Upregulated by Nitrogen-Deficiency in Wheat (Triticum aestivum L.) Grain

Glutathione reductase (GR) plays an important role in the responses to biotic/abiotic stresses and the regulation of protein in plants. In this study, cloning and characterization of TaGR2-1 and TaGR2-2, the homolog gene of barley HvGR2, from common wheat, were reported. The full-length cDNA sequence of TaGR2-1 (TaGR2-2) had an open reading frame of 1,490 bp encoding a deduced polypeptide of 496 amino acid residues with a predicted molecular weight of 53031.8 Da (52900.5 Da) and an estimated isoelectric point of 5.93 (5.93). TaGR2-1 was localized to chromosome 6AL and TaGR2-2 was assigned to chromosome 6DL. The multiple alignment result showed that TaGR2 was cytosolic glutathione reductase because it had not a chloroplast transit peptide. The TaGR2 expressed during grain development (from 5th to 38th days after flowering). The expressions of TaGR2 and enzyme activity of GR were both upregulated by nitrogen-deficiency in wheat. But the expression patterns of TaGR2 and the change pattern of enzyme activities of GR in wheat grain were not same for existence of chloroplastic GR at the early stage of development. GR's relation to the content of grain protein and high-molecular-weight glutenin subunit (HMW-GS) volume and the sodium dodecyl sulfate (SDS) sedimentation volume implied that GR in wheat grain could affect wheat gluten quality as glutathione (GSH).