PROCERA encodes a DELLA protein that mediates control of dissected leaf form in tomato

• Published in: The Plant journal : for cell and molecular biology 2008-11, Vol.56 (4), p.603-612
• Main Authors: Jasinski, Sophie, Tattersall, Alex, Piazza, Paolo, Hay, Angela, Martinez-Garcia, Jaime F, Schmitz, Gregor, Theres, Klaus, McCormick, Sheila, Tsiantis, Miltos
• Format: Article
• Language: English
• Subjects: amino acid sequences; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Biological and medical sciences; Botany; Cell differentiation, maturation, development, hematopoiesis; cell growth; Cell physiology; Cloning, Molecular; Crosses, Genetic; DELLA proteins; Development Biology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Genetic Complementation Test; Genotype; gibberellins; Gibberellins - biosynthesis; homeodomain proteins; Hormones; KNOX proteins; leaf development; leaf primordia; leaf shape; Leaves; Life Sciences; Lycopersicon esculentum - genetics; Lycopersicon esculentum - growth & development; Lycopersicon esculentum - metabolism; Molecular and cellular biology; molecular sequence data; Morphogenesis; Mutagenesis, Site-Directed; Mutation; Phenotype; Plant Growth Regulators - biosynthesis; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - metabolism; plant proteins; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - genetics; Plants, Genetically Modified - growth & development; Plants, Genetically Modified - metabolism; Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Plant - genetics; shoot meristems; signal transduction; Solanum lycopersicum var. lycopersicum; Tomatoes; Transformation, Genetic; Vegetal Biology
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2008.03628.x

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.