title: Minimal influence of G-protein null mutations on ozone-induced changes in gene expression, foliar injury, gas exchange and peroxidase activity in Arabidopsis thaliana L.
abstract: Ozone (O(3)) uptake by plants leads to an increase in reactive oxygen species (ROS) in the intercellular space of leaves and induces signalling processes reported to involve the membrane-bound heterotrimeric G-protein complex. Therefore, potential G-protein-mediated response mechanisms to O(3) were compared between Arabidopsis thaliana L. lines with null mutations in the α- and β-subunits (gpa1-4, agb1-2 and gpa1-4/agb1-2) and Col-0 wild-type plants. Plants were treated with a range of O(3) concentrations (5, 125, 175 and 300 nL L(-1)) for 1 and 2 d in controlled environment chambers. Transcript levels of GPA1, AGB1 and RGS1 transiently increased in Col-0 exposed to 125 nL L(-1) O(3) compared with the 5 nL L(-1) control treatment. However, silencing of α and β G-protein genes resulted in little alteration of many processes associated with O(3) injury, including the induction of ROS-signalling genes, increased leaf tissue ion leakage, decreased net photosynthesis and stomatal conductance, and increased peroxidase activity, especially in the leaf apoplast. These results indicated that many responses to O(3) stress at physiological levels were not detectably influenced by α and β G-proteins.
authors: US Department of Agriculture, Plant Science Research Unit, Raleigh, NC 27607, USA. fitz.booker@ars.usda.gov
authors: Fitzgerald
authors: F
authors: Booker
authors: Kent
authors: K
authors: Burkey
authors: Patrick
authors: P
authors: Morgan
authors: Edwin
authors: E
authors: Fiscus
authors: Alan
authors: A
authors: Jones
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D009154:Mutation; D018384:Oxidative Stress; D010126:Ozone / Q000009:adverse effects*; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D054046:Plant Stomata / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; D010126:Ozone; D009195:Peroxidase; D019204:GTP-Binding Proteins