Function of the plant gene induced by oxidative stress on the reduciton of lipid hydroperoxide

从拟南芥中克隆了包含磷脂氢过氧化物谷胱甘肽过氧化物酶（PHGPX）样蛋白启动子区域的基因。将该基因亚克隆到pBI101质粒中，使启动子基因与β-葡萄糖醛酸酶（GUS）基因融合。融合基因通过粒子轰击系统转移到豌豆根部。GUS基因在含0、50和100mM NaCl的MS培养基中瞬时表达。这表明phgpx样基因不是由氧化/盐胁迫诱导的。编码大麦phgpx样蛋白的cDNA在大肠杆菌细胞中表达，产生额外的蛋白。以过氧化叔丁基、过氧化异丙烯和过氧化氢为底物制备的无细胞提取液中未检测到PHGPX。测定了克隆细胞在含NaCl培养基中的生长能力。克隆细胞对NaCl胁迫的耐受性明显优于寄主细胞，表明phgpx样蛋白可能是植物抗盐/氧化酶的良好候选组分。

The gene that includes the promoter region of the phospholipid hydroperoxide glutathione peroxidase (PHGPX)-like protein was cloned from Arabidopsis thaliana. The gene was subcloned into a plasmid, pBI101, resulting the promoter gene was fused with the β-glucuronidase (GUS) gene. The fused gene was transferred to the root of the pea by the particle bombardment system. Transient expression of the GUS was shown in the roots cultured by the MS medium containing 0, 50, and 100mM NaCl. This result suggests that the PHGPX-like gene is not induced by oxidative/salt stress.A cDNA encoding barley PHGPX-like protein was expressed in Escherichia coli cells to produce an extra protein. The PHGPX was not detected in the cell-free extract prepared from the clone cells when tert-butyl hydroperoxide, cumene hydroperoxide, and hydrogen peroxide were used as a substrate. The clone cells were assayed for their ability to grow in the medium containing NaCl. The clone cells were much more tolerant to NaCl stress than the host cells, suggesting that the PHGPX-like protein would be a good candidate component of anti-salt/oxidative enzyme in plants.