University of SaskatchewanHARVEST
  • Login
  • Submit Your Work
  • About
    • About HARVEST
    • Guidelines
    • Browse
      • All of HARVEST
      • Communities & Collections
      • By Issue Date
      • Authors
      • Titles
      • Subjects
      • This Collection
      • By Issue Date
      • Authors
      • Titles
      • Subjects
    • My Account
      • Login
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      View Item 
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item

      The role of cytosolic glutamine synthetases in abiotic stress and development in Arabidopsis thaliana

      Thumbnail
      View/Open
      Final_version-thesis.pdf (1.753Mb)
      Date
      2011-04-01
      Author
      Ji, Yuanyuan
      Type
      Thesis
      Degree Level
      Masters
      Metadata
      Show full item record
      Abstract
      Glutamine (Gln), a major nitrogen source in plants, is considered a central intermediate that coordinates carbon-nitrogen assembly for plant growth and development. To maintain a sufficient Gln supply, plant cells employ glutamine synthetases (GS), including cytosolic GS1 and plastidic GS2 for Gln production. Previous work has shown that the GS1 is responsive to various environmental stresses. This study demonstrated the involvement of GS1s in Gln homeostasis and the role of GS1 in abiotic stress tolerance in Arabidopsis. The GS1 family is comprised of five isoforms in Arabidopsis thaliana. Gene expression profiling showed that GLN1;1, GLN1;3 and GLN1;4 had similar expression patterns and were upregulated by abiotic (salinity and cold) stresses, whereas GLN1;2 exhibited constitutive expression and no GLN1;5 transcript was detected under any of the conditions tested. Null T-DNA insertion mutants for the five GS1 genes were obtained. Only the gln1;1 mutant displayed enhanced sensitivity to a GS inhibitor, phosphinothricin, and to cold and salinity treatments, suggesting a nonredundant role for GLN1;1. Increased stress sensitivity in gln1;1 was associated with accelerated accumulation of reactive oxygen species (ROS), particularly in chloroplasts. To better understand the role of cytosolic GS isoforms, we generated two different triple mutant combinations. Triple mutant gln1;1/gln1;2/gln1;3 showed reduced growth at an early stage. The gln1;1/gln1;3/gln1;4 mutant is pollen lethal, indicating an essential role of Gln in plant gametophyte development. Collectively, our results establish a link between cytosolic Gln production, ROS accumulation, plant stress tolerance and development.
      Degree
      Master of Science (M.Sc.)
      Department
      Biology
      Program
      Biology
      Supervisor
      Yangdou Wei
      Copyright Date
      April 2011
      URI
      http://hdl.handle.net/10388/etd-04122011-152002
      Subject
      Arabidopsis
      pollen development
      ROS
      Glutamine synthetases
      abiotic stress
      Collections
      • Graduate Theses and Dissertations
      University of Saskatchewan

      University Library

      The University of Saskatchewan's main campus is situated on Treaty 6 Territory and the Homeland of the Métis.

      © University of Saskatchewan
      Contact Us | Disclaimer | Privacy