title: The mutant crispa reveals multiple roles for PHANTASTICA in pea compound leaf development.
abstract: Pinnate compound leaves have laminae called leaflets distributed at intervals along an axis, the rachis, whereas simple leaves have a single lamina. In simple- and compound-leaved species, the PHANTASTICA (PHAN) gene is required for lamina formation. Antirrhinum majus mutants lacking a functional gene develop abaxialized, bladeless adult leaves. Transgenic downregulation of PHAN in the compound tomato (Solanum lycopersicum) leaf results in an abaxialized rachis without leaflets. The extent of PHAN gene expression was found to be correlated with leaf morphology in diverse compound-leaved species; pinnate leaves had a complete adaxial domain of PHAN gene expression, and peltate leaves had a diminished domain. These previous studies predict the form of a compound-leaved phan mutant to be either peltate or an abaxialized rachis. Here, we characterize crispa, a phan mutant in pea (Pisum sativum), and find that the compound leaf remains pinnate, with individual leaflets abaxialized, rather than the whole leaf. The mutant develops ectopic stipules on the petiole-rachis axis, which are associated with ectopic class 1 KNOTTED1-like homeobox (KNOX) gene expression, showing that the interaction between CRISPA and the KNOX gene PISUM SATIVUM KNOTTED2 specifies stipule boundaries. KNOX and CRISPA gene expression patterns indicate that the mechanism of pea leaf initiation is more like Arabidopsis thaliana than tomato.
authors.affiliation: Department of Crop Genetics, John Ines Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Tattersall
authors.forename: Lynda
authors.initials: L
authors.lastname: Turner
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Knox
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ambrose
authors.forename: T H Noel
authors.initials: TH
authors.lastname: Ellis
authors.forename: Julie M I
authors.initials: JM
authors.lastname: Hofer
mesh_terms: D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D018532:Pisum sativum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; C405985:Knox1 protein, plant; D010937:Plant Growth Regulators; D010940:Plant Proteins