title: Plastid stromules are induced by stress treatments acting through abscisic acid.
abstract: Stromules are highly dynamic stroma-filled tubules that extend from the surface of all plastid types in all multi-cellular plants examined to date. The stromule frequency (percentage of plastids with stromules) has generally been regarded as characteristic of the cell and tissue type. However, the present study shows that various stress treatments, including drought and salt stress, are able to induce stromule formation in the epidermal cells of tobacco hypocotyls and the root hairs of wheat seedlings. Application of abscisic acid (ABA) to tobacco and wheat seedlings induced stromule formation very effectively, and application of abamine, a specific inhibitor of ABA synthesis, prevented stromule induction by mannitol. Stromule induction by ABA was dependent on cytosolic protein synthesis, but not plastid protein synthesis. Stromules were more abundant in dark-grown seedlings than in light-grown seedlings, and the stromule frequency was increased by transfer of light-grown seedlings to the dark and decreased by illumination of dark-grown seedlings. Stromule formation was sensitive to red and far-red light, but not to blue light. Stromules were induced by treatment with ACC (1-aminocyclopropane-1-carboxylic acid), the first committed ethylene precursor, and by treatment with methyl jasmonate, but disappeared upon treatment of seedlings with salicylate. These observations indicate that abiotic, and most probably biotic, stresses are able to induce the formation of stromules in tobacco and wheat seedlings.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK. jcg2@cam.ac.uk
authors.forename: John C
authors.initials: JC
authors.lastname: Gray
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hansen
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Shaw
authors.forename: Katie
authors.initials: K
authors.lastname: Graham
authors.forename: Rosemary
authors.initials: R
authors.lastname: Dale
authors.forename: Philippa
authors.initials: P
authors.lastname: Smallman
authors.forename: Senthil K A
authors.initials: SK
authors.lastname: Natesan
authors.forename: Christine A
authors.initials: CA
authors.lastname: Newell
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000598:Amino Acids, Cyclic / Q000494:pharmacology; D055864:Droughts; D008027:Light; D059828:Plant Cells / Q000502:physiology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000096:biosynthesis; D030821:Plants, Genetically Modified / Q000166:cytology; D018087:Plastids / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D036226:Seedlings / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D013696:Temperature; D014026:Nicotiana / Q000166:cytology*; D014908:Triticum / Q000166:cytology*
chemical_list: D000598:Amino Acids, Cyclic; D010937:Plant Growth Regulators; D010940:Plant Proteins; C023863:1-aminocyclopropane-1-carboxylic acid; D012965:Sodium Chloride; D011189:Potassium Chloride; D000040:Abscisic Acid