2017-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/713249摘要：氧化逆境下硫醇型谷胱甘&#32957;(GSH)被氧化為氧化型谷胱甘&#32957;（GSSG），是一個重要的細胞內氧化還原緩衝機制，反之，GSSG可再被Glutathione reductase(GR)還原成為GSH。水稻基因體中有3個GR，其中GR2 位於細胞質，GR1 和GR3 位於&#63854;&#63805;體/粒線體，傳統偵測植物細胞內GSH氧化還原狀態所用的方法為萃取整個細胞，再利用化學分析方法量測，導致無法偵測細胞中不同胞器裡面的氧化還原狀態，以及隨時間的變化。最近我們在GR的功能研究發現 GR3缺失突變體具有對鹽敏感的外表型，但抑制GR2表現卻會增進水稻的耐鹽能力，為了瞭解在不同胞器間GR表現和GSH/GSSG氧化還原動態變化的關係，試驗中利用roGFP這種具有感測氧化還原能力並可定量的蛋白質，藉由轉殖技術表達到水稻細胞的細胞質或&#63854;&#63805;體/粒線體，以釐清不同胞器間GSH的氧化還原和逆境的關係。此外，我們也發現抑制GR2表現的水稻株高變矮、一次枝梗減少，由於外加GA和GSH可回復株高，為了解細胞質GSH/GSSH的氧化還原和H2O2含量是否參與株高的調節，試驗中建立可誘導性大量或抑制GR2表現，及可誘導性大量或抑制同樣位於細胞質的ascorbate peroxidase 2 的水稻，以獲得細胞質內具有高、低比率GSH/GSSH、高、低含量H2O2 的轉殖水稻，再利用microarray分析這些水稻中和GA的生合成或訊號傳遞相關性，以期了解細胞質內GSH/GSSH或H2O2 對株高調節的機制。<br> Abstract: Under oxidative stress conditions, the tripeptide glutathione can switch from its reduced form (GSH) to oxidized glutathione disulfide (GSSG), and thus, forms an important cellular redox buffer. Conversely, GSSG is normally reduced to GSH by 3 glutathione reductase (GR) isoforms encoded in the rice genome, cytosolic GR2 and chloroplasts/mitochondrial dual-targeted GR1 and GR3. The majority of glutathione redox research has been based on the chemical analysis of whole-cell extracts, which unavoidably destroy subcellular compartment–specific information. Our recent results demonstrate that knockout of chloroplast/mitochondria-localized GR3 increases salt sensitivity in rice, whereas knockdown of cytosolic GR2 increase salt tolerance. To understand the compartment-specific importance of rice GR, the ratiometric redox sensitive roGFP2 protein will be expressed in cytosol and plastids of transgenic rice plants to monitor the redox changes of GSH. Furthermore, attenuated expression of cytosolic GR2 showed reduced plant height and numbers of primary rachis. To dissect the molecular mechanism, transgenic rice conditionally overexpress/knockdown cytosolic rice GR2 or ascorbate peroxidase 2 will be generated for the creation of rice containing high/low ratio of cytosolic GSH/GSSG or high/low contents of cytosolic H2O2. Microarray analysis of these transgenic plants will be conducted to analyze the relative importance of cytosolic GSH/GSSG ratio and cytosolic H2O2 content in the regulation of GA biosynthesis and signal transduction.穀胱甘肽穀胱甘肽還原酶水稻胞器GlutathioneGlutathione reductaseRiceOrganelle