Biochemical and functional study of a putative Lambda class glutathione-S-transferase gene in the wild soybean.

• Other Authors: Chan, Ching (author.)
• Format: Others
• Language: English; Chinese
• Published: 2014
• Subjects: Soybean > Genetics; Soybean > Effect of salt on; Salt-tolerant crops
• Online Access: http://library.cuhk.edu.hk/record=b6115699; http://repository.lib.cuhk.edu.hk/en/item/cuhk-1077644

我們在大豆的耐鹽候選基因中進行了篩選和調查，確定了一個穀胱甘肽-S -轉移酶（Glutathion-S-transferase ）基因（ GmGSTL1 ）具抗鹽特性，其表達量也跟隨鹽處理上調。系統發育分析表明，GmGSTL1 屬於LAMBDA 類，文獻對這類蛋白功能的記載甚少。我們在異源系統，包括煙草BY- 2 細胞和擬南芥，測試其保護細胞/植物對鹽脅迫的功能。結果表示GmGSTL1 轉基因細胞的活性氧積累比對照顯著降低，存活率也有所改善。同樣，轉基因擬南芥在鹽處理壓力下的症狀也得以緩解。為了進一步剖析GmGSTL1 的保護機制，我們在大豆葉片中提取多元酚，並發現兩個候選黃酮（槲皮素，山奈酚）與GmGSTL1 起相互作用。槲皮素的外源性應用同樣可以緩解細胞/植物在鹽脅迫下的症狀，表示槲皮素在功能上與GmGSTL1 相約。 === In a survey of candidate genes located in the salinity tolerance locus of soybean, we identified a putative glutathione-S-transferase (GST) gene (GmGSTL1) which was up-regulated in response to salt treatment. Phylogenetic analyses revealed that this putative GST belongs to the Lambda class, a plant-specific group with unknown functions. We expressed GmGSTL1 in heterologous systems, including tobacco BY-2 cells and Arabidopsis thaliana, to test its ability to protect cell/plant against salinity stress. Compare to the wild type control, we observed a marked reduction of ROS accumulation in transgenic cells under salt treatment, and their survival rate was also improved. Similarly, expression of GmGST1 in transgenic A. thaliana also alleviated stress symptoms under salt treatment. To further address the possible protective mechanisms of GmGSTL1, we identified two candidate flavonoid interactants (quercetin and kaemferol) of the GmGSTL1 protein from soybean leaf extract. Exogenous application of quercetin could reduce salinity-induced ROS accumulation in BY-2 cells and leaf chlorosis in A. thaliana. === Detailed summary in vernacular field only. === Chan, Ching. === Thesis (Ph.D.) Chinese University of Hong Kong, 2014. === Includes bibliographical references (leaves 80-104). === Abstracts also in Chinese.