College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, PR China.
Plant Physiol Biochem. 2011 Oct;49(10):1228-37. doi: 10.1016/j.plaphy.2011.04.005. Epub 2011 Apr 14.
A tomato (Lycopersicon esculentum Mill.) chloroplast glutathione reductase gene (LeGR) was isolated and antisense transgenic tomato lines were obtained. Under chilling stress, transgenic plants accumulated more H(2)O(2), leaked more electrolyte and showed lower net photosynthetic rate (Pn), maximal photochemical efficiency of PSII (Fv/Fm) and oxidizable P700 compared with wild-type (WT) plants. Transgenic seedlings were more suppressed in fresh-weight growth and lost more cotyledon chlorophyll. The decrease in the activity of ascorbate peroxidase (APX) was implied to be potentially relevant to the greater accumulation of H(2)O(2) in transgenic plants. Chilling treatment induced more decrease in the level of reducted glutathione (GSH) and redox ratio of glutathione in transgenic plants than in WT plants, but aroused more increase in GSSG in transgenic plants than in WT plants. Total glutathione displayed no change. Besides, chilling stress resulted in greater decreases in the level of reducted ascorbate (AsA), total ascorbate and redox ratio of ascorbate in transgenic plants than in WT plants, but led to equivalent degree of dehydroascorbate (DHA) increase in WT and transgenic plants. These assessments of glutathione-ascorbate cycle revealed that the decrease of glutathione reductase activity in transgenic plants affected glutathione regeneration, and consequently affected ascorbate regeneration and total ascorbate content. This resulted in a greater accumulation of H(2)O(2) and an enhanced sensitivity to chilling stress in transgenic plants. Moreover, a putative concept model of ecophysiological reaction was discussed.
番茄质体谷胱甘肽还原酶基因（LeGR）的分离及其反义转基因番茄系的获得。在冷胁迫下，转基因植株积累了更多的 H₂O₂，电解质泄漏更多，净光合速率（Pn）、最大光化学效率 PSⅡ（Fv/Fm）和可氧化 P700 比野生型（WT）植株更低。与 WT 植株相比，转基因幼苗的鲜重生长受抑制程度更大，子叶叶绿素损失更多。推测抗坏血酸过氧化物酶（APX）活性的降低可能与转基因植株中 H₂O₂的积累量更大有关。冷胁迫诱导转基因植株中还原型谷胱甘肽（GSH）和谷胱甘肽还原比的水平下降幅度大于 WT 植株，但诱导转基因植株中 GSSG 的增加幅度大于 WT 植株。总谷胱甘肽没有变化。此外，冷胁迫导致转基因植株中还原型抗坏血酸（AsA）、总抗坏血酸和抗坏血酸还原比的水平下降幅度大于 WT 植株，但导致 WT 和转基因植株中 DHA 的增加幅度相同。这些对谷胱甘肽-抗坏血酸循环的评估表明，转基因植株中谷胱甘肽还原酶活性的降低影响了谷胱甘肽的再生，进而影响了抗坏血酸的再生和总抗坏血酸含量。这导致了 H₂O₂的积累增加和转基因植株对冷胁迫的敏感性增强。此外，还讨论了一个关于生态生理学反应的概念模型。
