title: Auxin and its transport play a role in plant tolerance to arsenite-induced oxidative stress in Arabidopsis thaliana.
abstract: The role of auxin in plant development is well known; however, its possible function in root response to abiotic stress is poorly understood. In this study, we demonstrate a novel role of auxin transport in plant tolerance to oxidative stress caused by arsenite. Plant response to arsenite [As(III)] was evaluated by measuring root growth and markers for stress on seedlings treated with control or As(III)-containing medium. Auxin transporter mutants aux1, pin1 and pin2 were significantly more sensitive to As(III) than the wild type (WT). Auxin transport inhibitors significantly reduced plant tolerance to As(III) in the WT, while exogenous supply of indole-3-acetic acid improved As(III) tolerance of aux1 and not that of WT. Uptake assays using H(3) -IAA showed As(III) affected auxin transport in WT roots. As(III) increased the levels of H2 O2 in WT but not in aux1, suggesting a positive role for auxin transport through AUX1 on plant tolerance to As(III) stress via reactive oxygen species (ROS)-mediated signalling. Compared to the WT, the mutant aux1 was significantly more sensitive to high-temperature stress and salinity, also suggesting auxin transport influences a common element shared by plant tolerance to arsenite, salinity and high-temperature stress.
authors.affiliation: Horticultural Sciences Department, University of Florida, Gainesville, FL 32611-0690, USA.
authors.forename: Aparna
authors.initials: A
authors.lastname: Krishnamurthy
authors.forename: Bala
authors.initials: B
authors.lastname: Rathinasabapathi
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D018053:Arsenites / Q000633:toxicity*; D001692:Biological Transport / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D008163:Luminescent Measurements; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development; D012965:Sodium Chloride / Q000494:pharmacology; D017670:Sodium Compounds / Q000633:toxicity*
chemical_list: C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018053:Arsenites; D007210:Indoleacetic Acids; D017670:Sodium Compounds; D012965:Sodium Chloride; C017947:sodium arsenite; C030737:indoleacetic acid; D006861:Hydrogen Peroxide; D002374:Catalase
keywords: arsenite; auxin transport; indole-3-acetic acid; lateral roots; root development