title: ABA-deficiency results in reduced plant and fruit size in tomato.
abstract: Abscisic acid (ABA) deficient mutants, such as notabilis and flacca, have helped elucidating the role of ABA during plant development and stress responses in tomato (Solanum lycopersicum L.). However, these mutants have only moderately decreased ABA levels. Here we report on plant and fruit development in the more strongly ABA-deficient notabilis/flacca (not/flc) double mutant. We observed that plant growth, leaf-surface area, drought-induced wilting and ABA-related gene expression in the different genotypes were strongly correlated with the ABA levels and thus most strongly affected in the not/flc double mutants. These mutants also had reduced fruit size that was caused by an overall smaller cell size. Lower ABA levels in fruits did not correlate with changes in auxin levels, but were accompanied by higher ethylene evolution rates. This suggests that in a wild-type background ABA stimulates cell enlargement during tomato fruit growth via a negative effect on ethylene synthesis.
authors.affiliation: Radboud University Nijmegen, IWWR, Department of Molecular Plant Physiology, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands. lisette.nitsch@wur.nl
authors.forename: L
authors.initials: L
authors.lastname: Nitsch
authors.forename: W
authors.initials: W
authors.lastname: Kohlen
authors.forename: C
authors.initials: C
authors.lastname: Oplaat
authors.forename: T
authors.initials: T
authors.lastname: Charnikhova
authors.forename: S
authors.initials: S
authors.lastname: Cristescu
authors.forename: P
authors.initials: P
authors.lastname: Michieli
authors.forename: M
authors.initials: M
authors.lastname: Wolters-Arts
authors.forename: H
authors.initials: H
authors.lastname: Bouwmeester
authors.forename: C
authors.initials: C
authors.lastname: Mariani
authors.forename: W H
authors.initials: WH
authors.lastname: Vriezen
authors.forename: I
authors.initials: I
authors.lastname: Rieu
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D049108:Cell Enlargement / Q000187:drug effects*; D003681:Dehydration / Q000503:physiopathology; D005030:Ethylenes / Q000096:biosynthesis; D005638:Fruit / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D014644:Genetic Variation; D005838:Genotype; D007210:Indoleacetic Acids / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development*; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000502:physiology
chemical_list: D005030:Ethylenes; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D000040:Abscisic Acid; C036216:ethylene