Increased concentration of total glutathione improves vigor and stress tolerances of Arabidopsis

• Main Authors: Ko Ko, 柯克
• Other Authors: Tsan-piao Lin
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/20239945557156046563

碩士 === 國立臺灣大學 === 植物科學研究所 === 101 === Glutathione (L-γ-glutamyl-L-cysteinyl-Gly) is a simple sulfur compound composed of three amino acids and is the major non-protein thiol in many organisms including plants. Glutathione is involved in a plethora of cellular processes in addition to its role as an antioxidant and in the maintenance of cellular redox homeostasis. According to our previous observation, exogenously applied glutathione reduced form (GSH) could improve abiotic stress tolerance of Arabidopsis, especially under drought and salt stress. We suggested that GSH plays an important role to increase the vigor of plants. Whether endogenous elevated level of GSH also has the same effect needs to be evaluated. In this study, gain-of-function and loss-of-function of GSH synthesis mutants were obtained from different sources, and abiotic stress were applied to these mutant plants.GSH1 overexpressing lines accumulating much higher GSH content and much higher GSH/GSSG ratio showed higher germination rate and longer root length than wild-type plants in the salt-containing petri dish. Overexpression lines also showed some tolerance in drought and salt test, and exhibited higher survival rate in heat stress test. GSH1 overexpression influenced proline content, but didn’t influence ABA content. SAG12, the senescence marker gene, exhibited significantly delayed induction in GSH1 overexpression plants indicating the effect of GSH in the leaf senescence. We observed that higher GSH accumulation in shoot apical meristem under stress when the GSH was stained with monochlorobimane indicating. GSH protects preferencially shoot apical meristem and youngest leaves under stress. In conclusion, in this study we presented evidence to support endogenous GSH plays an important role to protect Arabidopsis under stress environment, especially the apical meristem and youngest leaves, and a new function in leaf senescence.