title: Tomato tos1 mutation identifies a gene essential for osmotic tolerance and abscisic acid sensitivity.
abstract: Osmotic stress severely limits plant growth and agricultural productivity. We have used mutagenesis to identify plant genes that are required for osmotic stress tolerance in tomato. As a result, we have isolated a novel mutant in tomato (tos1) caused by a single recessive nuclear mutation that is hypersensitive to general osmotic stress. Growth measurements demonstrated that the tos1 mutant is less sensitive to intracellular abscisic acid (ABA) and this decreased ABA sensitivity of tos1 is a basic cellular trait expressed by the mutant at all developmental stages analysed. It is not caused by a deficiency in the synthesis of ABA because the tos1 seedlings accumulated more ABA than the wild type (WT) after osmotic stress. In contrast, the tss2 tomato mutant, which is also hypersensitive to osmotic stress, is hypersensitive to exogenous ABA. Comparative analysis of tos1 and tss2 indicates that appropriate ABA perception and signalling is essential for osmotic tolerance.
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Málaga, Spain.
authors.forename: Omar
authors.initials: O
authors.lastname: Borsani
authors.forename: Jesús
authors.initials: J
authors.lastname: Cuartero
authors.forename: Victoriano
authors.initials: V
authors.lastname: Valpuesta
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Botella
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D018525:Germination / Q000187:drug effects / Q000502:physiology; D018551:Solanum lycopersicum / Q000235:genetics* / Q000502:physiology; D008353:Mannitol / Q000494:pharmacology; D009154:Mutation; D009997:Osmotic Pressure / Q000187:drug effects; D011392:Proline / Q000378:metabolism; D012639:Seeds / Q000254:growth & development; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D008353:Mannitol; D012965:Sodium Chloride; D000040:Abscisic Acid; D011392:Proline