title: Abiotic stress and phytohormones affect enzymic activity of 1-O-(indole-3-acetyl)-β-d-glucose: myo-inositol indoleacetyl transferase from rice (Oryza sativa).
abstract: Indole-3-acetic acid (IAA) conjugation is a part of mechanism regulating free auxin concentration. 1-O-(indole-3-acetyl)-β-d-glucose: myo-inositol indoleacetyl transferase (IAInos synthase) is an enzyme involved in IAA-ester conjugates biosynthesis. Biotic and abiotic stress conditions can modulate auxin conjugates formation in plants. In this study, we investigated effect of plant hormones (IAA, ABA, SA and 2,4-D) and abiotic stress (drought and salt stress: 150mM NaCl and 300mM NaCl) on expression level and catalytic activity of rice IAInos synthase. Enzymic activity assay indicated that all tested phytohormones affected activity of IAInos synthase, but only ABA had inhibiting effect, while IAA, SA and 2,4-D activated the enzyme. Drought and salt stress induced with lower NaCl concentration resulted in decreased activity of IAInos synthase, but 300mM NaCl had no effect on the enzyme. Despite observed differences in enzymic activities, no changes of expression level, tested by semiquantitative RT-PCR and Western blot, were detected. Based on our results it has been supposed that plant hormones and stress conditions affect IAInos synthase activity on posttranslational level.
authors.affiliation: Department of Biochemistry, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland. Electronic address: annaciar@doktorant.umk.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Ciarkowska
authors.affiliation: Department of Biochemistry, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland. Electronic address: maciejost@umk.pl.
authors.forename: Maciej
authors.initials: M
authors.lastname: Ostrowski
authors.affiliation: Department of Biochemistry, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland. Electronic address: anjakubo@umk.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Jakubowska
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D055864:Droughts; D007210:Indoleacetic Acids / Q000494:pharmacology; D012275:Oryza / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D020156:Salicylic Acid / Q000494:pharmacology; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D015084:2,4-Dichlorophenoxyacetic Acid; D012965:Sodium Chloride; C030737:indoleacetic acid; D000217:Acyltransferases; C025402:indoleacetyl-glucose-myo-inositol indoleacetyl transferase; D020156:Salicylic Acid
keywords: IAA; IAA ester conjugates; IAInos synthase; Oryza sativa; SCPL acyltransferase