title: PROCERA encodes a DELLA protein that mediates control of dissected leaf form in tomato.
abstract: Leaves of seed plants can be described as simple, where the leaf blade is entire, or dissected, where the blade is divided into distinct leaflets. Mechanisms that define leaflet number and position are poorly understood and their elucidation presents an attractive opportunity to understand mechanisms controlling organ shape in plants. In tomato (Solanum lycopersicum), a plant with dissected leaves, KNOTTED1-like homeodomain proteins (KNOX) are positive regulators of leaflet formation. Conversely, the hormone gibberellin (GA) can antagonise the effects of KNOX overexpression and reduce leaflet number, suggesting that GA may be a negative regulator of leaflet formation. However, when and how GA acts on leaf development is unknown. The reduced leaflet number phenotype of the tomato mutant procera (pro) mimics that of plants to which GA has been applied during leaf development, suggesting that PRO may define a GA signalling component required to promote leaflet formation. Here we show that PRO encodes a DELLA-type growth repressor that probably mediates GA-reversible growth restraint. We demonstrate that PRO is required to promote leaflet initiation during early stages of growth of leaf primordia and conversely that reduced GA biosynthesis increases the capability of the tomato leaf to produce leaflets in response to elevated KNOX activity. We propose that, in tomato, DELLA activity regulates leaflet number by defining the correct timing for leaflet initiation.
authors.affiliation: Plant Sciences Department, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Jasinski
authors.forename: Alex
authors.initials: A
authors.lastname: Tattersall
authors.forename: Paolo
authors.initials: P
authors.lastname: Piazza
authors.forename: Angela
authors.initials: A
authors.lastname: Hay
authors.forename: Jaime F
authors.initials: JF
authors.lastname: Martinez-Garcia
authors.forename: Gregor
authors.initials: G
authors.lastname: Schmitz
authors.forename: Klaus
authors.initials: K
authors.lastname: Theres
authors.forename: Sheila
authors.initials: S
authors.lastname: McCormick
authors.forename: Miltos
authors.initials: M
authors.lastname: Tsiantis
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D005838:Genotype; D005875:Gibberellins / Q000096:biosynthesis*; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010641:Phenotype; D010937:Plant Growth Regulators / Q000096:biosynthesis*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014170:Transformation, Genetic
chemical_list: D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D018749:RNA, Plant