Wingsle G, Karpinski S
Department of Forest Genetics and Plant Physiology, Faculty of Forestry, Swedish University of Agricultural Sciences, Umeå, Sweden.
Planta. 1996;198(1):151-7. doi: 10.1007/BF00197598.
Glutathione reductase (GR; EC 1.6.4.2) and superoxide dismutase (SOD; EC 1.15.1.1) are two well-known enzymes involved in the scavenging of reactive oxygen intermediates. However, little is known about the regulation of Gor and Sod genes in plant cells. To obtain information about hypothetical redox regulatory mechanisms controlling Gor and Sod gene expression we artificially enhanced the levels of reduced and oxidized forms of glutathione (GSH and GSSG) in Pinus sylvestris L. needles. Scots pine shoots were placed for 12 h in beakers containing 5 mM GSH, 5 mM GSSG or water. Increased levels of both GSSG and GSH were observed in the GSSG-treated needles after 3 h. In contrast, only the GSH level was increased by the GSH treatment. Thus, the GSH/GSSG ratio increased up to 15-fold during the GSH treatment and decreased approximately two-fold during the GSSG treatment. The GR activity was significantly higher (60%) when GSSG was applied, without any apparent change in the amount and isoform population of GR or accumulation of Gor gene transcripts. This indicates that the GR activity increased per se in the GSSG treatment. The level of cytosolic CuZn-Sod transcripts was decreased significantly by the GSH treatment without any change in enzyme activity. The chloroplastic CuZn-Sod gene generally showed a more stable transcript level in the different treatments. However, a similarity between the cytosolic and chloroplastic levels of CuZn-Sod transcripts could be observed in different treatments. This suggests that the redox state of glutathione plays an important role in the in vivo regulation of CuZn-Sod gene expression in plants.
谷胱甘肽还原酶（GR；EC 1.6.4.2）和超氧化物歧化酶（SOD；EC 1.15.1.1）是两种参与清除活性氧中间体的著名酶。然而，关于植物细胞中Gor和Sod基因的调控知之甚少。为了获得有关控制Gor和Sod基因表达的假定氧化还原调节机制的信息，我们人工提高了樟子松针叶中还原型和氧化型谷胱甘肽（GSH和GSSG）的水平。将苏格兰松嫩枝置于含有5 mM GSH、5 mM GSSG或水的烧杯中12小时。3小时后，在经GSSG处理的针叶中观察到GSSG和GSH水平均升高。相比之下，GSH处理仅提高了GSH水平。因此，在GSH处理期间，GSH/GSSG比值增加了15倍，而在GSSG处理期间降低了约两倍。施加GSSG时，GR活性显著更高（60%），而GR的量、同工型群体或Gor基因转录本的积累没有明显变化。这表明在GSSG处理中GR活性本身增加。GSH处理使胞质CuZn-Sod转录本水平显著降低，而酶活性没有任何变化。在不同处理中，叶绿体CuZn-Sod基因的转录本水平通常更稳定。然而，在不同处理中可以观察到胞质和叶绿体水平的CuZn-Sod转录本之间存在相似性。这表明谷胱甘肽的氧化还原状态在植物体内CuZn-Sod基因表达的调控中起重要作用。
