谷胱苷肽及其类似物诱导大豆活性氧和植保素的积累

 谷胱苷肽(Glutathione, GSH)是一种重要的抗氧化剂, 但它能诱导一些豆科等植物的防卫反应。本文采用大豆悬浮细胞体系分析了GSH及其衍生物诱导大豆活性氧和大豆植保素大豆素(glyceollin)的积累。GSH诱导大豆素和黄苷元的积累, 并有一定的剂量关系。N-乙酰半胱氨酸、巯基乙醇、二硫苏糖醇没有激发子活性, 但氧化型谷胱苷肽能激发大豆的防卫反应。在巯基被修饰的化合物中, S-对叠氮苯甲基谷胱苷肽和S-对氯苯甲基谷胱苷肽能够诱导大豆素和H₂O₂的产生, S-己基谷胱苷肽也能诱导一定量的H₂O₂积累。水杨酸和蛋白酶抑制剂DFP能增强芫菁素或者酵母细胞壁激发子诱导的大豆素积累, 但对GSH没有相似的增强效果。这些结果表明GSH中的巯基并不是激发所必需的, 大疏水基团能弥补巯基的作用。另外, GSH诱导大豆素积累信号传导途径可能与芫菁素的不同。

Glutathione and its derivatives induce active oxygen species and phytoalexin accumulation in soybean cells

Glutathione,an important antioxidant can induce defense responses mainly in legumes.In the study,the effect of GSH and its derivatives on the accumulation of phytoalexin and active oxygen species in soybean suspension-cultured cells were analyzed.GSH induced accumulation of soybean phytoalexin glyceollin in a dose-dependent pattern.Other antioxidant such as N-acetyl cysteine,mercaptoethanol,and dithiothreitol did not show any elicitor activity,whereas oxidized GSH induced synthesis of glyceollin.Some of the thiol-modified compounds induced both H2O2 and glyceollin accumulation.Salicylic acid,or protease inhibitor,diisopropylfluorophosphate can not potentiate the accumulation of glyceollin induced by GSH,but showed potentiation activity on cantharidin or elicitor from yeast cell wall fragments induced phytoalexin accumulation.These results suggested that large hydrophobic group could compensate the elicitation activity of thiol in GSH.